FatSecret will tell you your Recommended Daily Intake for the speed of weight loss you want and the level of exercise you do. A lot of people seem to find FS's RDI a bit high (I agree), so you can check it against a few others and edit it here yourself. Two other websites that give good RDI's arehttp://www.webmd.com/diet/calc-bmi-plus
I like the fat2fitradio calculator because it tells you how many calories to eat to lose weight as well as how many calories you will be eating when you are the weight you want to be. It helps clarify the calorie deficit.
I also low ball the exercise activity level. That will make heavy exercise days bonus days rather than expected exercise for my daily RDI. I can always increase my intake by a 100 calories or so on a heavy exercise day, but if I put it in as my daily level it really bumps up the RDI.
Under 1200 calories a day is generally considered unsafe....That's just for basic survival. If you were eating under 1200 regularly doing WW, your body was reacting to the starvation by hoarding fat. Definitely get those calories up just a little, and you'll probably start losing again. Good luck!