My bad. I think that if you cut the carbs and increased protein you'd see a lot of change. Really, you should be able to just cut back on the carbs, and walk, and not hit any plateaus, albeit a very slow process.
For leg strength...there really isn't much you can do as far as the bone goes. Your best bet is to try out the carb cuts. You need to stay away from and non-whole grain pastas, breads, etc. My honest opinion is don't eat fruit either.
I'm not a professional, I've been hoping for second opinions this entire time.
Have you tried cycling with low resistance? (not a real bike, an exercise bike)
Exercise bikes are far easier on the legs than BOTH jogging AND running. Running, if I remember correctly, essentially places four times your body weight worth of pressure on the knees.
Also, you could get in a swimming pool, float on your back, and do bicycle exercises. You can do it on ground too, doing it in a pool can open you up to more opportunities!