I agree with Sonya. First, you need to get her down for a nap every 2 hours or so. If she's overtired, she'll tend to wake up sooner from her naps. At around 1.45 hours or so, keep an eye on her to see if she's exhibiting tired signs. These could be tired-looking eyes, rubbing her eyes, grouchiness, grunting, whining or even crying, and/or yawning. (It's possible that she won't exhibit these, either, but if she's awake for over 2 hours, try putting her in her crib anyway. If she wants to play, she's not tired. If she complains or cries, she's tired.)
Second, do not offer bm before she goes to sleep. She will definitely complain (you may have to do PU/PD for this) but you shouldn't give in. I speak from experience... it's easier to stop this now than it will be later. If you make sure that she eats well during the hour or so after she wakes up, she won't need that amount before the nap, and she'll nurse a lot better when she wakes up.