You should limit yourself to 1200 calories a day. Do at least 4 days a week exercise, step classes, swimming or even walking and you should see a difference in 4 weeks but you must stick to it. Also avoid things like sweets, fizzy drinks. I find the best meal for losing weight is fresh chicken with lots of vegetables. Drink lots of water! I always make sure I have one day where I can eat anything it seems to take the pressure off :) I hope this helps as it worked for me.
You have not mentioned your age which is necessary part of a formula to calculate calorie consumption called Harris-Benedict principle. Anyhow, you can reduce your weight up to 30-40 lb in 2 months. A women requires 2200-2500 calories per day. If you have easy life style, it means sedentary then you need minimum calories per day. Usually, 60% of consumed calories is used daily. So, you can restrict your daily calories consumption up to 1500. Alone this will not work. You have to avoid taking fats, sweets and bakery foods, restrict daily protein intake up to 28 gram per day and eat low carbohydrate diet. Go for brisk walk of one hour or swimming for one hour will also give good results.
That would depend on so many factors. What your height is now.
How old you are. What your activity level is like