What are easy to fix low calorie low cost meals/How much weight can I lose at 16?

I'm going on a diet. I'm 215. I've lost about 60 pounds but for a few months,I've stopped losing. I was on steroids so it's really hard to lose that weight. I'm going to join a gym and do swimming, kickboxing and yoga/pilates. I don't like eating more than 1500 calories a day. It's just too much for me. I'm not wanting to lose weight quicker or something but I'm just not someone who eats a lot. I hate junk food and sodas. Anyway, my family doesn't want to cook a seperate meal for me so what are so cheap and easy ideas? I'm 5'8 and 16. I would have started going to the gym sooner but we didn't have a car and the buses don't run anywhere near the gym I'm going to. Also if I did 2 hours of swimming 3days/week and kickboxing/yoga/pilates 1 hour each week, how fast would I lose weight/gain muscle? I would like to lose more than 1-2 pounds a week because it would take me years to lose weight. I'd like to be around 140. I have an athletic build. Please post any useful information. Thanks.