L.O.
Wow! How about therapy?? Has that been brought up or done yet? I am afraid that by putting a restraining order on your step-child you are just going to add to the anger that is already obvious. You didn't say anything about the father's opinion, does he feel a restraining order is needed?
There is always a lot of anger in a divorce and new family situation but I'm just afraid if you go after a fly with an elephant gun you could be adding more problems as time goes on.
Good luck and find some family therapy.
L.