Any trainers out there that can offer some advice?

I am disabled with mild Cerebral Palsy that effects my walking. When outside I have recently started to use a walker. I also have arthritis in both hips, lower back, neck, as well as the starts of osteoperosis. I have been on the treadmill walking about 20 mins at 1.2 speed. Also found that I can do the eliptical (only for 5 min) and have started to lift weights to tone my flabby arms. I have often wondered if a disabled person burns more at the gym than a normal person? My doctor has suggested I go from 137 down to 110 to make my walking easier-so thats why I am here. Any suggestions on other workouts? If I lift weights sitting or laying down will I still have the same result as a normal person? BTW I don't have a current pic-the one posted is me at 110-5'3"