I hate my Bitchy sister in law ?

She is not just "bitchy", she is just plain CRUEL. It sounds like she is very jealous of you and wants to put you down every chance she gets. You should really feel sorry for her because she is so insecure that she has to keep trying to impress everyone with what a wonderful person she thinks she is. The best thing that you can do is avoid being around her and ignore her rudeness.