My parents want me and my sister to have a relationship ...?

Try to understand your parents perspective. Of course they are going to want to see you guys getting along. And I'm sure deep down you love her. Even if you don't like her. Just ask that your parents respect how you feel because they only know a small portion of what you've dealt with. Tell them you understand why they feel like they do, but that you just can't deal with her right now, maybe in the future things will change.