1000-1200
Calories is incredibly low for your current weight... and it's only going to hurt your
weight loss progress in the long run...
you might not want to add in 1000
calories overnight, but absolutely increase the amount you're getting over time - maybe add in 200 -400
calories a day for a week - then when you stabilize at 1200- 1400 then add in more.
I'm not expert, we've got a few of those floating around but I'd be willing to bet that you shouldn't be below 2000
calories a day and probably even higher.
The lower your weight goes the less
calories you will need so you want a higher starting point and gradually cut back.