Hi again! I'll bet you're tired of hearing from me.
Raise your calories slowly. Go up to 1300 for a week or two, then up to 1400, etc., keeping your exercise the same. Don't panic and try to increase your exercise at the same time.
You can expect *some* weight gain at first because if your metabolism has slowed down, it is now so efficient it will just love being able to store something ahead... But don't worry. Stay with the plan. You may also see a sudden *drop* in weight as you increase calories. I've seen this happen with a few different posters over the years.
Either way, make your plan and stick to it--don't suddenly switch again in three days. Ride it out for at least a couple weeks and see what happens.
Jay