Weight loss

I want to lose 30-45 pounds before I go back for my senior year at the end of August. That sounds outrageous, I know! I don't expect to hit that goal but a start would be nice! Does anyone know the amount of calories I would have to burn vs what I take in to do something like that? I'm thinking about workin out 30 minutes to an hour each day, followed with a protein shake. I want to stop drinking pop and eat better, with maybe one cheat day per week! Has this worked for anyone? If you have a success story you can share it and say what you did! :) I need to stay dedicated!