Assault and Battery questions...?

Ok, I have a court date tomorrow. I have a subpoena to be a court. I am the victim. Let me give the story as quick as I can.

I was at a friends apartment. UNKNOWINGLY to me, my g/f was outside, and was talking bad to a girl or guy about him cheating on her sister. Ok, I swear I didn't know this was going on. I was inside drinking a beer, probably my 3rd one.

I step outside to smoke a cigarette. The small argument had already subsided, but I never knew it even happened. The guy (whom I somewhat know, but never really had but one conversation with him) said something to me. I didn't hear him. I start walking to talk to him. No idea he was mad.

We meet halfway on some steps, and he is standing 2 steps above me and says "I'm going to hit you". I completely thought he was joking. I was like "What, man?" He said it again. I said "What's wrong, we are friends." This is really how it happened. I still wasn't sure he was even mad. He pushed me once, I held my hand up to shake and he pushed me again harder, I grabbed for the rail, and as I was coming back up he started punching my head/face. He immediately ran off somewhere, and my friend lead me back into the apartment and helped me stop my nose from bleeding.

Well, someone called the cops, that guy had done left (to go get his brother to fight me, CRAZY, I know). The cop told me to go to the hospital. I said I couldn't afford to. He said the guy that hit me would have to pay. So I go. I have never experienced this before. Little did I know that I would get the bills and have to get my money back somehow.

Well, tomorrow is my court date for this. What am I looking at, what do I need to say? Help me, I'm nervous.