It would be difficult for us to give suggestions about what might be safe to do, without knowing the details of your condition and being able to evaluate you in person. I would ask your doctor if they would be able to give you a referral to see a physical therapist who can design a set of exercises specific to your needs. If not, finding a personal trainer in your area who's experienced with this type of thing might also be a good option.
Hope that helps,
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford