Getting Custody of my child from his father

I am a 25 years working mother. My marriage was done before 4 years ago. I have a 3year and 7month old baby boy. I was stayed in my husband's house at the early times. At that time he was working in bangalore. He comes to home between two or three weeks. Before marrige he and his parents were agreed to let me either continue my education or join for a job. But after marriage i hot pregnant in a month.That time i had some health issues. Because of that i coun't join college or go for a job. Because of this health issue I was not being able to do my household works because of that my husband's parents where not happy of me. They have started to complain my parents about i am not doing any work at home and this made an issue in the house. After the delivery the the complaint about me in house started to raise slowly this made my hustnad a decision to take me and my son with him to Bangalore so after one year he took us to there and stay with him. When i was living with him in Bangalore he has scold me often and even had beaten me 3 times for talking about his parent's doing mental toucher to me and the matter of that coun't being able to adjust there with them. He blackmailed me to stay with his parents by saying seperating my son from me. Because i could not stand without my son and pressure i agreed to live with his parents and came back to them. I joined for a job and started going for Sunday classes as adegree student so that i can stay away from his family so that i can escape from his parents mental toucher. My husband didn't allow me to visit my parenthood with my son. Because of these all stress i had to leave his house and come and stay in my home. But they didn't allow me to take my son with me. They forced on the baby and took him away from me. Now i want mu baby back. I want to know what are the legal possibilities so that i can get back my son to live with me.