Hi i'm 5'2 and weigh around 9st 10. I've been trying to eat around 1200 calories a day, but i find that really low, and when i finish work (i work 6pm-10pm) i'm always really hungry and end up eating too much.
check the stickied thread in the nutritio forum - you'll find a formula that you can use to give you an approximate number of calories - based on age/height/weight and activity level...