In order to loose weight in quick time you can have control on your diet. There are some diet plans that you can follow and do regular exercise and walk. You will find the results in quick time.
There is no way to safely lose very much weight... But you can start your weight loss program now and continue it after the wedding, so when something else comes up, you'll be ready for it.
Start by giving up sodas, sweets and processed foods... That's the best thing you can do for yourself... Also take a 30 minute walk every day...