I found Pilates far better than yoga. Will need a qualified instructor though - and beginner Pilates, not Pilates using that Pilates 'machine' that is pushed out on the internet (lot of people get the two muddled, invest in the 'machine' and find that they get/can get injured by using!)
Also Tink, vist Manatee (Cindy's) profile, there you will find various exercises specific to AS put together BY Manatee. Very good indeed.
I am presently having physio at the local hospital, doing me a power of good. Have got a lot of mobility back, even neck mobility, which I would not have thought possible. Am soooo pleased. The exercises we are doing are much like to what Manatee has posted. You can find Manatee and her exercises by going to the user section, click on the Ms, and Manatee is about 8/10 person down. Can recommend.
Might even bring the exercises to the attention of your gym instructor and perhaps do a Manatee exercise in replacement of those exercises that are a no-no for you at the gym? Just a thought.
Go well -