how can I save her

My best friend and I were at a party.  She was drunk. Her attacker had eyes on her the whole party and I was the only one who noticed. I am shook. I was terrified for her. But he wasn't anywhere to be seen after the first hour I thought he left and she would be safe...but about two hours later I knew she was drunk. She needed to go pee I was drunk as well but not nearly as much as her. She went to the bathroom and I went to see how she was and I opened the door and the bathroom was empty it was dark and cold. My heart dropped. She wasn't anywhere. I finally started checking rooms. I was panicking because as a best friend it is my job to make sure she is okay. She is my sister from another mister. I walk up to the door and for someone I felt a chill. I then hear a some voices and and then I herd a deep and scary voice. I knew. The door was locked I freaked. "I'm busy" said the scary deep dull voice. After 1 minute of shaking and trying to break the lock it broke the door swung open and my best friend. Naked practicality not even awake. He doesn't stop. I lost it. My heart broke in a million pieces and I attacked him. I saw candle holder and I hit him once on the head but it wasn't enough. Rolled off and tried to fight back but I hit him again. He murmured. I hit him again and again and again it still wasn't enough he stopped moving. Finally someone walked by and noticed. Everyone but not everyone came I covered her up and a couple people help me get her into the back seat of the car and everyone had questions but I was so numb so hurt and so angry. Finally everyone just went back inside like it was nothing I saw her monster walk out of the door and not even one head turned nobody cared but me he looks over at the car and sees me. His face has already started to swell blood on his lip and his fist held tight. I did not hide I did not feel anything but anger. I felt so cold. I would do it again. I wanted to start that car and end the monster.  But I started the car and drove away. I got the picture of his license and I will give the police his information. I'm so hurt..I'm broken.. she woke up and she remembers... I don't know how what to do what can make it okay...