What do you do when you have children with a Narcissist?

I left my N when my son was 7 months old. I have also moved over 400 miles away from him. He has full custody of his three other children who I was close with but he won't let me talk to them anymore. I have recently filed for a restraining order against him, unfortunately the court didn't grant the temporary orders because of the distance and lack of any recent incidents between us. I know that there will be though because i cannot leave me alone, its only a matter of time, especially since I have his son. I am doing everything I can to keep him away but I am afraid to have him have any contact with my child. I have seen first hand the physical and emotional abuse his other children have endured and I am truly terrified that he will harm my son in some way. Last time I saw him he already was talking about him coming to live with him when he was "of age." The mind games have already started.