Painted smile type of day

Chris, my little (almost) 7yo got beat up at the bus stop this morning! Now, we've had problems in the past. Aerrik would say kids shoved him off a snow hill he was climbing (big ass snow hills), I told him not to climb when they're around. Kids throw snowballs, iceballs, and rocks at Aerrik and Chris. I tell them go inside the community center. Kids pushed Chris down. I said next time it happens grab an adult in the community center to identify the brats and I'll call their parents. Well I get a call from the school today, it's Aerrik using the office phone. He says a couple kids were throwing snowballs at Chris and BEATING him with their backpacks!!! I asked him if he knew who they were and he said he "only" knew two of their names, which leads me to believe there were more involved. One is a 5th grader in Aerrik's class, the other is a 4th grader who was held back (big surprise!). So I had Aerrik put the school scretary on the phone, told her the situation and told her I wanted these kids names because I wanted to press charges (I am SO tired of this shit!). Well she said she can't give me their last names but said she knows who they are and the school will look into and she'll let me know what's going on. Now, I trust her, she's a nice competent lady, but I'm also going to be checking my school directory tonight, and if I can find these punks I'm gonna have an officer accompany me to their houses for a little chat. I also called the police department and told them after spring break (next week) I want an officer presence at the bus stop until this BS ends. This is getting ridiculous! I'm afraid I might be overreacting but what else can I really do? Chris will learn bully-busting skills in taekwondo but he's only had 2 classes! ARGH!!!!!!!