I know this is a bit late, so hope it still helps. With my daughter, between 15 and 18 months we stopped giving her a night time bottle. Instead, we gave her a sippy full of milk (about the same amount) in her highchair. At first she didn't drink that much, so we started giving her a small snack with it so she would drink more...and that seemed to work. We struggled witht he snack though, trying to find a snack that would help fill her up but not get her reenergized (fruit DID NOT work!). Another thing is that we used to give the bottle and read stories after bath time before putting her down for bed. Since we started the sippy we didn't want to disrupt her night routine of a calm bath, books, and snuggle time to go back downstairs and get a snack and milk, so we started giving that to her BEFORE we did an other night routines so not to disrupt them. That seemed to work better. After awhile, we just slowly took the snack and milk away. Now, at 2+ yrs old, she doesn't eat anything from dinnertime on (around 6:00).
Hope it helps.
A.