I agree with Trish and Ruru - you need a routine that signals bed (very helpful for later on as well when they are bigger). Also if they get all their calories in the day, they wont need as many at night, and therefore wont wake up as often for a feed.

Also, try and put her straight back down after a feed, even if she is still awake. Unless she is upset, it will give her the hint that nights are for quiet and sleeping.

Good luck hun - she will get it eventually, it just takes a bit of work!