What temperature are you fermenting at? If it is low, the yeast may work very slowly.
If you are in the yeast's ideal range, then your mash temp may have been a little high leaving you with more unfermentable sugars. If this is the case, it is probably done since it has been stable for two weeks. How does it taste?
As for the airlock, I wouldn't worry about it. As long as it was just a crack and there are no insects in your fermentor, you will probably be just fine.
Also, you are probably going to get some posts about racking to a secondary. Many brewers on this forum only rack if they are doing something special (complicated addition or dry-hop) or aging for long periods. IF it is stuck, then racking removes the wort from the bulk of the yeast needed to finish. (Although three weeks should be plenty.)
I would say let it sit for two more weeks, and if the gravity is still the same go ahead and bottle.
Edited for spelling ...