Hey, sounds like you're getting everything straightened out. Your vet's diagnosis and treatment are right on, as Roger said in the other post. One of my iguanas had severe MBD presenting with several broken bones when I got him, and thanks to treatment similar to what your vet has prescribed he happily runs around and can do most everything a normal iguana can.
The only things I would add are: restrict your iguana's access to things he can climb. Sunlight is magic for iguanas; if you live somewhere reasonably warm this time of year, even a few minutes a day will work wonders. I feel my iguana benefited from recieving an emergency calcium shot from the vet, you might inquire about that. Your iguana must be only about 8 inches away from the UV light to benefit him, and this light must be replaced about every six months.
The first sign my iguana was getting better was that he attempted to use his broken back legs, instead of dragging them. It is only recently (1.5 years after finding him) that he has started to raise his tail up high when going to the bathroom, as healthy iguanas do. He still can't get it as high as he should be. And he still stutter-steps sometimes, but I'm not sure if that's an effect of the old MBD, or just him being goofy.
The most important thing is being vigilant about following the vet's directions. You can give your iguana a long, healthy life by following through on your good intentions. Like Roger V., I see no reason why your iguana should not recover fully.
Two questions: Are you changing your iguana's diet? That is to say, do you know what caused the MBD? Also, why aren't you happy with your vet?
Let us know what happens- best of luck.
Erin