My grandmother is suffocating me!?

My mothers girlfriend forced me out of home and the only place I could go was my grandmothers (my mums mother). Now my grandmother is sending me insane. For example, im an atheist and she keeps shoving Catholicism down my throat (and please don't abuse me christians) which is fine for her I just don't want her beliefs forced on me. She is always telling me how I should renew my faith because atheists, buddhists, jews, pretty much everyone who isn't catholic or christian is going to hell. Im apparently not allowed to be with a black man because interracial relationships are a sin, ity is a sin, before marriage is a sin. I cant take drinks to friends houses although im 18 because I will get drunk and do something horrible. After she watched that Liam Neeson movie taken I was told im not allowed to go to france like I want to do one day. Another time I applied for a job and when they called me in for an interview we found it was apparently a bit dodgy so my grandmother made me swear I wouldn't answer the phone in case i was tracked down and killed. Im also sick of her comments about muslims and how they are abusive to women forcing them to wear, and I quote "loin cloths on their face", and that they can't be trusted wearing what they do because they could be hiding bombs under the clothes. Now I don't know what was worse, treading on eggshells around my mothers girlfriend or my grandmothers racism and prejudice. How do I deal with her?