It's really sad when religion breaks up families like yours, notawitness. Be assured that she and the JW's are the ones who are in the wrong. Family and love are the most important connections we have in the world, and any religion that tries to break that up is totally wrong - and on top of that, there is so much more that they have to answer for. Unfortunately, like many other members here have pointed out, you may not be able to do anything about it - and that is hard. Giving her lots of space and love, like others here suggest is good. Once you learn more about the negative aspects of the religion and how to attack it, choose your moments and start bringing them out. She won't get any of the negative feedback from the JW's. They guard and hide their hypocrisy like a mother protects her son, and most witnesses are totally ignorant of the organization's lies. As to how to bring them to her attention, I really don't know. The book by David Reed sounds good. The witnesses have such strong indoctrination techniques, that even I wouldn't attempt it until I had read something like that.
Best wishes and Happy Birthday!