The biggest thing that helped me come out was the Bible. I was shown scripture after scripture of things that the WT did that wasn't in line with what the Bible actually taught (real Bible translations compared to their New World's Translation). Once I saw they didn't teach correct doctrine, the rest fell in place--the false prophecies, the leaders making up their own theology, etc. You need to come at her with facts, not emotion. You can e-mail me for further information, if you want.
But of course, that's a long process (and maybe even after that she'll never leave), and I can understand you want an immediate resolution. Look at the facts: I can see your main concern is your future children, which is very practical to consider. Not just the blood issue (which is too serious to leave up in the air--it's a life or death decision, please remember that), Jehovah's Witness children can have no Christmas, no birthday's, no Thanksgiving, they can't say the pledge of allegence in school, 4th of July fireworks is considered wrong because of the patriotic aspect, they can't be apart of after school things like football, cheerleading, etc., they can't have any friends who aren't Jehovah's Witnesses. They are expected to go in field service with their parents on Saturday's when most kids are leading normal lives playing with friends. They are expected to not only study for all of the meetings with their parents (five meetings a week), but they are pressured to comment also. THE LIST IS ENDLESS! These are JW rules, and not from our loving heavenly Father. Jesus came to lighten our load, not make it heavier. The older a JW kids get, they are expected to do more (for boys, they are expected to have duties at the Kingdom Hall and if they don't do it, they are considered not in "good standing"). Just is just words, but the truth is, there is so much JW kids are put through, emotionally and mentally. I was raised a JW, and like me and others on this board know, it's an unfairly hard life to grow up in.
You are dealing with a cult, this is not just "some religion" as I'm sure you're starting to see. And I hate to tell you this, but I know of many situations like this were the kids grow up as JWs, and KIDS AND THE WIFE end up leaving the "worldly" mate because he/she never accepts it as the "truth". It happened to a friend of mine, and now he is left alone, his three kids willingly gone to service the WT with their mom.