Domestic violence and cruelty against Husband

I have been subjected to cruelty and domestic violence by my wife for past many years. She is abusive and shouting on me for long time and threatening me with legal consequences and harassment from her family. I live in a different city from my native place. My mother visited few months back but my wife subjected her to immense torture and eventually my mother returned to her home. My wife continued to abuse me and quarrel with me. She also abused me physically and destroyed all evidences against her. After physically harming me and making a big drama she left our home with my 9 years child to her matrimonial home since 10 days. My wife's family will not let her come and she can't decide on her own. I can't live without my child. They are also threatening of filing case of physical abuse on her and even demanding to name property in her name. Please suggest me appropriate legal action against them to get back my child. Also, please help me what should be my approach when I talk to them.