If she drinks formula, then I agree with Suzanne about mixing with the formula gradually. (AND I agree that sippy cups just encourage children to be careless with their drinks! The only time I used sippy cups was when eating out.) If she still doesn't like the taste of the milk, then she may just not like milk. Lots of people think cows milk is for cows, anyway! (Although I think that makes me a cow!) If you feed her lots of other good foods, she can get her calcium from yogurt and greens and broccoli and the American diet is rich in protein.
If you are still nursing her, I would say that maybe she isn't ready to wean. This is just my opinion, but I think 12 months is on the young side to wean. I allowed one of mine to wean herself at 11 1/2 months and then regretted it - she was the clingiest toddler I had and I decided she had needed more mommy time than she knew herself.
J.
Christian homeschool mom of three beautiful grown girls, one wonderful son-in-law, two terrific teens, and one rambunctious, first-class boy