Jw wont reason because they cant, they are JWs. I know your desire to help her and use logic but you gotta listen here. They cant reason. I made the same mistake with my parents. Now they dont talk to me at all. There is LOGICAL argument that will help her and now she is against you. If you wanna rescue her you need.
1.- BUILD RAPPORT (even if its needed for you to go back to the meetings, or whatever it takes, she needs to trust you)
2.- Cognitive dissonance (hence the references to mirror her behavior although thats a little hard to do well, usually this dissonance will come from other sources but not you.
watch this video and see how they did it.
http://www.youtube.com/watch?v=yCb9bLkNu2g&playnext=1&videos=dSE_Hn_JPpE&feature=mfu_in_order