How can I tone up?

"Toning" means building muscle / burning fat. If you have no access to weight, you'll have to go bodyweight. Pushups, crunches, situps will help a little, but if you really want to see results you'll have to get near some weights. Is there no gym near you? Can you get some dumbbells from any store near you? Craigslist in your area?

If you want to add some muscle, you'll probably want some more calories in your diet. Here's a great resource:

http://liamrosen.com/fitness.html