Have you looked at a calorie calculator to determine your maintenance calories? Once you get an idea of where to start (and this is just a guideline, as everyone is different), you can figure out how much to cut your calories to lose. Cut 500 calories a day to lose one lb a week. Cut 1000 per day to lose 2 lbs a week.
I just plugged in some numbers to "calories per day calculator" to get an idea of your maintenance requirements, and I guessed 22 for your age and lightly active for your activety level. It shows 2013 calories/day to maintain your current weight. So, without increasing exercise, you will not be able to lose more than about one lb a week without cutting your calories to a dangerous level. You should eat at least 1200 calories a day unless under a doctor's care. I'd shoot for one lb a week, and cut your calories to about 1500 (which is where you are now) and then really work on that attitude about exercise to see if you can't make more progress.
I was guessing your age and activety level, so you may want to go do this for yourself. Here is the link.
http://walking.about.com/cs/calories/l/blcalcalc.htm
I also tried this with your age at 26 and that came out to 1988 maintenance, so you might want to stick to around 1450....but your metabolism may be faster or slower than this calculator, so you have to try it for a few weeks to see what is happening for you.