S.G.
Juice and milk in bottles at this age are no good for their teeth. Especially if they are taking naps and bed time with them. You need to be strong and just toss all the bottles and offer only sippy cups. You'll hear a few days of crying and unhappiness but it will be over quickly and you'll both be better for the experience. My son didn't like hard plastic spouts on sippy cups at first so I got the trainers from gerber. I can't find the ones I used but they were like these.
http://www.drugstore.com/products/prod.asp?pid=165736&...
After about a month with these, I was able to get the playtex ones with the hard spout because he had gotten the hang of sippy cups.
Good luck!
S.