Unless you do some quickie fad diet for the short term, you're only going to be able to lose about 5 or so pounds in the time you have.
Figure out how many calories you need to maintain your current weight, then eat 500 less every day and burn 500 more. That'll be a calorie defecit of 1000 a day, 7000 a week = two pounds a week.
To figure out how many calories you need, go here:
http://www.soyouwanna.com/site/syws/loseweight/loseweight2.html#para2.1To figure out how many calories you burn doing certain exercises, go here:
http://primusweb.com/fitnesspartner/jumpsite/calculat.htmAnd remember that you don't have to burn those 500 all at once. Two 25 minute sessions on an elliptical, for instance, will probably burn off 500 calories a day. (Really work it, though, and do the interval/weight loss course.)
Personally, I've also found that cutting back my dinner carbs helps. I'm not a supporter of low-carb dieting, but the way my body works, a diet with (healthy) carbs concentrated in the earlier part of the day keeps me from pigging out at night. That's just me, though.
Good luck!