OK, your resolve is about to be tested. C_Y_P was not exaggerating when he detailed the work involved. I'd say 2-5 years of concerted effort with a willing partner to get them out of the grasp of the society. I am a non-JW, loyal, loving, intelligent and determined, and I have been at it for five years. Even if you succeed, she will likely have to renounce her relationships with JW family and friends. It is a soul-wrenching experience, and no shoulders are wide enough to carry all the pain.
For this to work she must herself want out and grow a backbone. You can't interfere with free will, and you can't build muscle for someone else. That means you must stand on the sidelines encouraging, but not interfering with her independent thought process. Even in the end if she picks the society over you.
I find a good litmus test is to ask to be introduced to the family. If she is too embarrassed to do that, you know firmly where you stand, and it's not first in her heart. Love her, but leave her.
And, finally, don't convert to make her happy. We watched on the board the slow progress of a young man who chose that path. His misery was palpable.
[Edited to add] I found it! The young man's name is Buck. http://www.jehovahs-witness.com/member/16001.ashx telltruth, I suggest you read all his posts. I sure hope Buck is doing OK.