I would also add a tube of metanium - having tried lots of things it is the only one that I have found that gets rid of ds's nappy rash.
Depending on the pram she has got, a thing to put on the handle that holds a cup or bottle (or even one for her and one for the baby!). Toys-R-Us now sell them and so does the Baby Catalogue.
In fact the baby catalogue have several bits and pieces that would be useful. They do a nice 'snuggle blanket' made out of cotton flannelette which is nice and soft, can be used for all sorts (towel, floor mat, extra sheet, summer blanket, etc) and a snip at £4.50. A wriggly toy that can be attached to a car seat or pram is handy, lots of people give 'proper' toys, having something that you can take out and about with you is very useful.
Which reminds me, a small bag made up with a few nappies and travel sizes of all the other bits and bobs that you need to change a baby, including a couple of disposable changing mats would be nice because she could just pop it in her bag and be ready to go out. Travel shops now have some nice wipeable pouches that are pretty cheap or even a cosmetics pouch or small sponge bag would be good.
Don't know if this would be insensitive if she is trying to bf but if she is also going to be expressing they can be useful. Mothercare do a self sterilising bottle that you can just put into the microwave for 90 seconds, wait another 90 seconds and it is ready. It is also handy if you are out travelling as you don't have to lug other sterilising stuff around with you. If you are tired and a baby is screaming for their food, having to wait 10-15 mins for a steam or microwave steriliser to do its stuff can be a very long time!
Finally (I know I have gone on too long, sorry!), if you are any good at taking pictures, put a voucher in there to say you will take a nice portrait of mum and baby (and other child, think you say she has already got one?) - it is so easy to think you are taking pictures and get to a year old and realise you have got lots of nice snaps but no proper pictures that you have planned in advance.
Enjoy putting it together - I am sure your friend will love receiving it!