Beginners Exercise - Knee Ins
These are good, especially if you are still having a hard time moving. Not only will you get to work your arms by holding you up but also your core and abs as well as your knees and hips with no impact. Start with 10 total (5 each side) and try to get through 3 sets and work your way up to 10 sets.
Here is a video of the exercise if the picture is not clear: