Patching and Plastering - Ceiling repair due to roof leak

Last year we had a leak on our roof which resulted in a our ceiling to form a "bubble" while dripping water. We had the roof repaired which stopped the leaking, but when the water subsided from the "bubble" in the ceiling it caused it to crack. Is there a quick way to repair the small area on the ceiling with the problem, or do we need to have the entire ceiling repaired and painted?

By 'bubble' in your ceiling, I assume you mean the drywall became waterlogged and sagged between the joists. If it just pulled loose from the joists, you may be able to reattach the drywall to using a few drywall screws. Most likely, however, you will need to cut out the damaged ceiling area from the center of one joist to the center of the next and replace with new sheetrock, taping and mudding in the usual manner, then painting the repaired area (if not the whole ceiling).