I’ve been victim of aggravated assault. which legal steps should I take? I want to sue the guy!?

This evening I was sitting in my house around 10pm. I heard something hitting my window, like someone throwing stones. It hit 3-4 times very hard. I thought they were the next building neighbor’s kids. They ring the bells and escape sometimes. I thought they’re playing. I went out to my back garden and walked to the space between two buildings, where also is the basement floor entrance. I saw a guy between the buildings (that hallway looking space is connected to back garden also) and I said hey what’s going on here? (Thinking that he has an idea who’s hitting the windows) I thought he was the basement floor neighbor. He didn’t say a word and started running towards me cursing. You m.effer etc. He had something in his hand, like a discman. And I said hey wait I live here!! He didn’t stop and raised his hand, I started running inside but he threw me the discman in the head at a very close distance and it hit back of my head as I was running from him. I got in the house and he chased me to the door, entering my garden. I closed the door and my 2 friends called the police immediately.

My head was bleeding like a fountain. We put some towels and pressed until the ambulance came. The police arrested the guy (turned out to be my neighbor downstairs. He has a separate entrance between buildings, and I enter the building from other side, so I really didn’t know he was my neighbor. I never saw the guy before) and he told the police we were making noise. We do have parties some weekends and we are very loud when we party, but tonight even the TV wasn’t on. But after listening to me, the police took him.

I went to hospital, they made 7 stitches and worst part is as it in my head, they couldn’t stitch it. They used staple gun on my head after local anesthesia.

The police told me to come to the station to testify. I don’t have health insurance so I will probably receive $2000-3000 hospital bill, which I can’t pay.

What steps should I take legally? Anything to mention while testifying? How about the hospital bill? What’s gonna happen to him? How am I gonna be safe in my house after this event?

Thank you for your replies.