the average for women is 2000 cals a day, although if your body is used to starving it might hang on to those cals like mad.
i would suggest you see a dietician and be honest about your past and present eating habits. they can advise you accordingly and that way you have more control if you loose or put on weight.
basically, if you eat healthily, you should be ok and shouldnt put on boat loads of weight. (unless you're really underweight in which case your body will normalise to its healthy weight range.)
try eating a healthy brekkie and maybe a piece of fruit during the day and a salad for lunch and some steamed veggies with grilled chicken for dinner. try get good grains into you too to keep you regular and cleaned out.
above all- dont stress, get lots of sleep and drink loads of h20 every day!