Trying a different type of formula or even a different style bottle could help. My 2nd boy was the same way. We had these bottles that were supposed to help keep extra air out of his stomach but they didn't. We finally settled on the bottle liner style. Other people I know swear by the Dr. Brown bottles. Just pick up different styles and try them out (do a few feedings with one style before you try another to give her time to settle into it).
Another thing to consider is that she isn't getting a good seal on the nipple of the bottle so she is getting extra air while she is drinking. My son did this too. Then he would cry and get even more. His gas pains were almost unbearable for all of us involved.
Also, try burping her more often than you are now and maybe try smaller bottles or even bigger bottles. It is all about trying to figure out what works for them.
If you think she is constipated then do give her juice. Pear juice seemed to help my guy out more than anything else. I would dilute it with water in varying amounts until we figured out what worked best for him. We gave him those bottles twice a day. Less if he was having messy diapers that weren't just pebbles.
Good Luck! (P.S. My son had gas problems even after we got him past his worst phase, he got a lot better around 12 weeks but it took him about 9 months to become a happy baby, hang in there. It will pass)