How to lose weight in about 9 months without any exercises requiring footwork?

I want to know some healthy lose-weight tips before I go to college, which is about 9 months from now. I have a foot problem, and can't really walk well so jogging and any sport requiring footwork is out of the picture. Plus, I'm not very athletic either. I'm about 70 kg. I want to lose at least 15 pounds. I need some diet tips.