Bad hips & knees

 I need help. I have arthritis in both knees and gout in my hip. If I have a gout flareup I can just about walk. I try walking outdoors. With winter coming and cold weather I will be walking on my tread mill. I also have a stationary bike (which really bothers my knees. Oh yea I also have a buldging disc in lower back and neck. So I'm afraid of trying heavy exercising .
Once I decided on finally doing surgery I have lost over 20lbs. Any ideas of excersizes I can do.
Thanks

 Do you have a pool available to you?  Water aerobics is much easier on the back and other joints.