My advice is a little different. I was a JW girl in a similar situation when I left.
A lot of JWs secretly question the religion but may never act on their doubts. Your GF has acted on hers in the past, and I suspect she is still having those doubts, since she is crying so much and driving by your house. I mean, according to the JW beliefs, she should be relieved and happy that she broke it off with you. Why the tears? Why the driving by your house? To me, that shows a longing for you rather than happiness that she broke it off.
If she transfers to another store, moves away, or otherwise totally eliminates all contact with you, then that's a signal for you to give up on her. If she hasn't done that yet, try to be kind to her and let her know regularly that you miss her, still love her, and believe you two were meant to be together. Avoid being pushy about it, as that will just push her back towards the JWs. Given time, she may come around and find the courage to leave the organization for you. She may not. The ball is in her court now. Only time will tell.
I'm not saying to hold a candle in hope out forever, but maybe for a while to see what happens.