enough calories

I am trying to lose 10 pounds by June 1st. I am taking hour long turbo kick classes at my gym 2-3 days a week. What is a realistic calorie goal? I plugged the info. into the goals section of my page and it is only giving me 1200 calories a day which seems like so few.

I'm 5'3, 141 pounds.

I find I don't lose a thing on 1200 calories its too low - if anything it puts your body into starvation mode and I personally start gaining. I usually have between 1500-1700 calories per day and burn off about 200 per day in exercise. I have set my loss to 0.5 per week, this gives you more calories to play with and you have the energy to exercise. When I only have 1200 calories I haven't got the strength to function properly.