Racist family! what do i do?!?

My parents are racist against mostly african americans and arabians, my mom hates mexicans but my step dad doesn't. My moms mexican! And my step dad and my biological dad are mexican! She only wants me to date white guys. The problem is I have friends of every race and I mean every race! She so against my black friends though especially the guys. She says black people are pushy and stinky and mexicans are controlling. I have a friend whose half mexican and half black who asked me to prom. My parents were so against it that they tried to bribe me with money not to go and in the end they forced me not to go by saying they weren't paying for the dress or anything. I cried and had to tell him I couldn't go. He was so disappointed when I told him why. I just can't get my mom to see how wrong she it. My grandmas racist so I know that's where my mom gets it. How can I get both my parents to see how ignorant they sound!?