How many calories a day should I eat to lose weight and how much calories should I burn?

I weigh 149lbs and i'm 28 years old. I work out at the gym 3-4 days a week for an hour and a half. Right now i'm eating 450 calories a day and burning 550 calories at the gym. I really need to know how much calories I should be eating to lose weight with the amount of exercise i'm doing and how many calories should I burn.