Parents harassing me and not letting me marry the boy I love

Hi Sir/Mam, I am a 25 year old girl working in Hyderabad, I am in love with my a boy who is of inter religion. On fine day we spoke to our parents about this and wanted to convince about it. His parents are willing to arrange for our marriage only once my parents are ok with it. But my orthodox/control freak family is not willing to agree because of religion issues and thinking about society. My parents has tried a lot to convince me by speaking ill about my boy friend and his family so that i would drop off from the relationship. But I was not convinced to my parents words. One fine day they have called me home and they house arrested me from that day and did physical and mental abuse and threatened me if i ran away they kill me and my boy friend wherever we are. It's been 8 months mostly that i am locked now and did not give any mobile phone or anything. Now I want to marry my boy friend but before that I want to go to police station and file a complaint a case against my parents so that i could get free my parents 1st and then i can marry my boy friend. Can you suggest me what action I should take and what cases I should file in police station. I also scared what if my parents bribe Police and they will again send me back with my parents.