Here's some things to try - I empathize with you, we ended up at a gastro-intestinal specialist with ours due to the reflux and constipation.
Try these maybe:
Do the bicycle with her legs alot, it helps with the gas, also rolling her from side to side while doing this helps get the gas out without much effort on her part (doing lower leg twists from right to left with them pushed inward toward her tummy).
Little Tummies Infant Gas drops, we used them in about every other bottle - ask your pharmacist for the right doseage for her age - completely safe.
We did breast milk for a while, then for medical reasons, I had to stop due to transfer of medication in the milk. We were then put on Enfamil w/ Iron, 3 weeks later, we switched to Nutramigen(sp) ICK and EXPENSIVE. We stayed on that for 6 weeks, then slowly transitioned (with our gastro-specialists supervision and advice) to Carnation Good Start - and WHAT A DREAM! It's so gentle, and very close to the consistancy of breastmilk too, oddly.
Sitting up for at LEAST 30 minutes after each feed is imparitive. We used the bouncer chair or the carseat for sleepy times, then moved him to the crib after this time had passed.
Using a passy right after burping/feeding, this helps the "keeping it down" part of digestion to continue. This was a pediatrician recommendation, and then also mentioned by the gastro specialist.
Burp, Burp, Burp - at that age, we burped every 1/2 to 1 oz.
Watch out for over feeding, this one will invite reflux!!! It's almost better to have several little feeds then one big one with a reflux baby.
And finally, ask your ped. about adding a bit of plain rice cereal to the feed (you'll have to get a faster flow nipple for bottles) 2-3 times a day to assist with the reflux, some doctors even prescribe Enfamil AR which has added rice starch in it to help with this.
For constipation:
Prune juice made our baby terribly gassy, so we used 1 tsp of baby stage 1 applesauce in his bottle 2 x's a day, this made the poop come more naturally for us as the fruit has natural juices in it for the bowel to absorb along with the milk/water.
Good luck, and trust me, it passes! Ours went away and seemed like overnight at about 3-4 months!