Domestic violence - My girlfriend's dad punched me in the face, what should I do?

So my girlfriend and I are constantly having relationship problems where we argued almost every week for the past 4 yrs. To give you a little about her background, she was diagnosed with bipolar years ago before she met me, I actually found this out 2 yrs after I met her from her family. She is very insecure and has an anger issue. She accused me of many things in the past which are far from the truth. But to cut the long story short, we had an argument today and we were shouting and yelling at each other back and forth. When it was my turn I shouted right in her in her face. She then started pushing me and hitting me so I pushed her back. She tripped backwards over a room heater behind her and when she fell, she grabbed me and that is when her dad approached me from behind and punched me in my left eye. I swung back at him and my girlfriend broke up the fight and tell her dad to stop, "he didn't do anything". Her dad has been living in my house for the past 2 years because when he first moved to California, he needed a place to stay so I told him since my house is pretty empty ( I only live there part time), he can rent a room from me and so he did since none of his kids wants to move in with him. Now, after this incident, I feel extremely uncomfortable having him around my house. After the argument when the dusts settled, me and her decided to break up and separate. I offered her dad the money back at a prorated amount for the remaining of the month and told him to move out immediately but he refused. He said he has 30 days time frame to move out legally. I was upset at the time but I remained calm and said fine. I spoke with my attorney and the sherriff in my county, they said if I file a report meaning to press charges, they can have him arrested for assaulting and have him move out immediately at the same time. But right now I just don't know what to do, since he refused to leave immediately, how should I handle this situation? I really don't want to escalated things because for one, he is my ex-gf's dad but I really want him to move out asap. But he didn't budge even after I offered him money back so he can move out today. Should I do call the police go the hard way or should I just let him move out in 30 days and let it go? Please advice!!!