Child's mother is violent and a loose screw! What can I do?

Well to start, this woman is my ex girlfriend. We have not been together in six months. We were engaged to be married, but I did what she calls the unforgiveable and cheated one night when I was drunk. I confessed it to her when I didn't come home all night. She was very calm about it. Then when I came home from work, all my stuff was packed on the porch and the locks were changed. I called the police and they couldn't do anything since the house is in her name & I wasn't getting any mail there. Then after that, I came outside one morning and all four of my tires were slashed. Her three sisters threatened me with a knife to tel them where the other woman lived. They all attacked her. Her brother threatened me with a gun when I tried to reconcile with her. She spit in my face and cursed me out. Then I got court papers in the mail. We went to court for visitation of our son. Her whole family hates me because I cheated on her. We do custody exchanges at the police station because I was trying to talk to her everytime I went to the house. But she would get violent and she threatened to blow me away to hell if I ever mentioned getting back with her again. How do I settled the beef with her family? They're all ex convicts by the way, for violent offenses.