I Wanna Lose Weight By July 4 and August 24!!!!!!?

I need to lose 20-40lbs by July 4 and August 24 maybe lose half in each of the deadlines,because I have to go to my bratty cousins who is like stick skinny and is really mean and well she weighs like 80lbs the last time I saw her(that was 2-4 years ago) and I weigh 140lbs. I eat 1 bowl of Rasian(or however u spell it) Bran for breakfast,a salad for lunch and w/e is cooked for dinner unless its not healthy or I dont like it then i have a salad.I usually dance around the house and do this machine thing and magazine workouts(I get them at the library) and I walk my dogs,swim for 2-6 hours a day play basketball(I'll be playing a lot more since my cousin is coming over I think tomorrow and hes staying for about a week) I just run around chasing my little kitties around the yard for a long time and I practice pitching outside and chasing the down.I only get on the computer for about 1-3 hours a day and thats mostly at night. I get in my bed at 9pm and draw til 9:30pm and then go to bed