Your best bet would be to plug all your data into FitDay or another calculator online. Your metabolism will vary too much to hazard a guess...depends on height, age, activity, how close you are to goal weight. etc. In order to estimate how quickly you can lose to your goal, you would need to know your deficit (calories burned minus calories consumed). From that, and the knowledge that it takes a deficit of 3500 calories to lose a pound, you can calculate how long it will take.
I'm not sure how fast you want to lose, but keep in mind two things, just as an aside: first, safe and sustainable loss is considered 1-2 pounds per week (unless you are extremely overweight and in the first weeks you will lose rapidly in that case), and that some people find that weight loss stalls if calories are too low, as the body attempts to compensate and slows the metabolism. This happens for some but not others; everyone that it happens to has a different baseline, but it is generally bandied about that 1200 is about as low as you should go on a daily basis in order to prevent this.
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days