How do you get along with a selfish sister-in-law?

She is my husbands, brother’s wife. I have to spend a lot of time with my husband’s brother and his wife. We all have a family cabin together and my husband and his brother work for the same company. I dread anytime I have to go to a work party, to the cabin, or to anything where the sister-in-law will be. My husband already knows that I dislike her and he tries to like her, but thinks she is frustrating too. She always talks about herself and NEVER asks anyone about anything they are up to. She has been in the family for about four years now and I have been in the family for about six years and she knows NOTHING about me or my husband. The other night my husband and I and his bro and the sis in law went to a football game together. We had to pick them up and when she got in the car she didn’t even say hi to us but loudly acknowledged how cool and smart she is and none can be as “smart, beautiful and cool” as she is. She also rudely announced to us of a exotic trip she is planning and how she makes more money than her husband... blah blah blah. Of course I'm gagging. That was all just during the 15 minute car ride. When we got to the game she didn’t say a word to us. Other times that I have to be around her she talks about cruises and cool trips she has been on and that she has had so many life experiences, but she fails to ask any of us what we have done. She was a cheerleader in high school and a singer/performer in college. She has been in a couple small productions which I had to go to and she did this whole dance thing on my husband’s lap! I was so pissed! Why couldn't she do it on her husband’s! I also hate eating around her because she is VERY thin and I’m curvy but used to feel confident and I loved my body. She says I should work out (which I do) and will make remarks about how I eat and it really hurts my feelings. She is a really beautiful talented girl but she is so self absorbed. How do I deal with this and not let her get to me? I am so tired of going out of my way to say hi and talk to her when she turns the conversation about her and how "cool" - actual quote - she is. I love being around people and the more the merrier, but I can't stand her. Help!