I'm afraid this is one of those situations that you are just going to have to tackle! You've said yourself that you don't want to end up bringing him into bed and once you've had the new baby and are up feeding, I'm sure you will feel even more strongly about this!
So, this is a great time to teach your toddler to sleep through, before your new baby arrives.
My advice would be to choose a weekend (or at least 3 consecutive days when your husband doesn't have to get up for work) and make a plan.
I would suggest that you get your husband to go in when your toddler first wakes up. He can offer a drink of water but don't turn the lights on, try not to pick him up, give him a little cuddle and lay him down. You can rub his back but in a quiet, calm voice, tell him it's sleep time and leave the room. This whole process should take no more than a couple of minutes. Then set your alarm or a timer for however long you think is appropriate (I would recommend no more than 15 minutes). If he still crying after that time then you have a turn going in and doing the same thing. If you both show your toddler the same, consistent approach and that he is not getting anything other than some water and a quick pat on the back, he will soon realise it's not worth screaming for.
Basically our children are always looking for where the boundary is. They will push and push to see what they can get away with. If he knows that eventually you will give in and let him into your bed, he will keep pushing. However, if he realises that no matter how much he pushes, he won't get anywhere, he will soon decide he might as well go back to sleep! I'm not suggesting he'll do this without some resistance but he will eventually.
The reason we do this is for the health, safety and sanity! of everyone concerned. It is far healthier for him to learn to sleep through the night (for you and for him). It is far safer for him to sleep in his own bed rather than in yours and you will find it much easier to be a 'nice' Mummy if you've had a good night's sleep!
Of course you love him and it's because of this that you can now give him the gift of learning how to sleep through the night!
Although Baby Wise doesn't have a chapter specifically addressing unique 'premmie issues', in the chapter on multiples, it does address some of the things you may find relevant to a premmie as most multiples are born early.
The main thing I have heard over the years is that premmie babies just take a lot longer to do everything and are REALLY sleepy. Obviously her corrected age is just 2 weeks if she is now 7 weeks. I would not be expecting a 2 week old to yet settle themselves to sleep. However, if you are consistently finding she wakes a little way into her nap, I would definitely make sure she is well burped before being laid down. Again, at this stage, I would say 45 minutes is too long to let her cry and I'm sure you would agree! The tricky thing in these early weeks is that babies can get over stimulated so easily (especially premmies) and if they do, they find it very hard to settle themselves.
May I encourage you to read the chapter on multiples in the book and then please keep asking more questions via email and I'd be more than happy to help you.
Remember to enjoy every precious day with her :-)
Many newborn babies seem to have their nights and days mixed up! Rest assured, it does settle down and if you ensure they are getting full feeds consistently throughout the day and letting them wake naturally at night, you will soon find them falling into a more 'socially acceptable' pattern of being awake during the day and sleeping more at night.
A common mistake new parents make is to wake their babies every 3 hours during the night. Unless your baby is sick and specifically requires the extra feeds, it is better to let them wake naturally at night. You can be confident that they WILL wake when they are hungry so enjoy as much sleep as you can get :-)
For more information on this and other 'sleep' questions, please see our DVD Babywise Bliss.
In Babywise Bliss, we talk about the '45 minute intruder'. This is when babies wake during the light part of their sleep cycle (usually around the 30-45 minute mark). It is really common and if you are sure there is no physical reason for her waking, it may be just that she needs to learn the skill of resettling herself.
On page 196 of the Baby Wise Book, they do address young babies waking up early from their nap. It may be worth having a quick look at what they say.
I would encourage you to use the Healthy Baby Growth Charts found in the back of the book and keep a close eye on her overall health. 5 weeks is very young and she will soon sort out her routine if you remain consistent.
Keep enjoying every moment - it passes really quickly!
There are a couple of main factors I would consider when addressing night time sleep issues in a baby this age.
Firstly, what does you day time routine look like? i.e. are they getting consistent feeds and sleep during the day?
Secondly, remember that sleep breeds sleep so it is unlikely that she is getting too much at this stage (which many parents are concerned about)
Thirdly, this is around the age many babies need to begin on solids. If your baby has consistently been sleeping through the night but begins waking up hungry at this age, it is a good indicator that they are probably ready to begin solids.
You just need to be aware that the small amounts most of them eat in the beginning, don't really affect their appetite (and therefore sleep habits) for about a month. If you are still concerned that your baby is hungry, try adding in an extra feed during the day.
For more information on introducing solids, please see Baby Wise Book 2
It is always difficult to assess what may be happening via email but there are 2 things which come to mind when parents describe their 6 week old crying instead of sleeping, even when the parents know the baby is tired.
Firstly, is there an underlying physical cause? i.e. does she have an ear infection so when you lay her down her ears hurt. Or, does she have some reflux so when you lay her down it hurts. Obviously I would recommend a thorough check from your paediatrician and sometimes just elevating the top end of her mattress is enough to keep her on a slight angle when she is laying down and that can alleviate some of the issue. We just put a rolled up towel under the mattress to raise it slightly.
Secondly, something I always found around this age was that our babies got over tired VERY easily. Once they are over tired it is much harder for them to put themselves to sleep. On our DVD Babywise Bliss, we cover 'tired signs' and what to look for so you can put them to bed as soon as they are tired. Some babies at this stage will only survive a very short wake time and sometimes the time it takes to feed and change them is enough of a wake time. I would recommend watching for some of those tired signs and seeing if she needs to go to bed sooner. This may solve the issue in that first nap of her not being able to self settle.