Losing weight in 2 months?

I'm 59 kg (130 pounds) and want to be 50kg (lose 20 pounds) within 2 months. I ate relatively well (although room for improvement), dance for 1 - 1.5 hours (on thursdays), for 4.5 hours on saturday, and I usually use the exercise bike most days, and I also do clinical pilates on Wednesday's for about 50-60 minutes. Any meal plans, diet suggestions/tips or references to any weight loss information that would work for a teenager would be greatly appreciated. I've found weight loss is really hard for me and desperately need that extra help! I want to lose it naturally and safely though, so I look healthy and fit.