Do a quick google search of "how many calories can I eat in a day" there you can find a calculator somewhere on the nutrition.about.com or health.about.com forget which. There it will ask you male/female, current weight, goal weight and it will tell you how many calories you should eat to maintain your weight, lose weight slowly, or by a pound a week without exercise.
You will need more calories if you are exercising though.
2008 - 235 lbs Started WW
2010 - 179 lbs Stopped WW & Major Life Changes
Current - 200lbs
Goal - 160 lbs
Sporadically Blogging my Journey at myweightloss.kilianwalker.com
I'm a Gamer at Heart, and a Graphic Designer