Hi Raddy,
Sorry I might have misunderstood your message - I thought that you had approached the teacher and she had spoken to the boys already, and then the bullying happened again. I would not suggest "escalating" the complaint if she hadn't had a chance to deal with it first. If however she has tried to deal with it (with limited success) I would try an alternative route (someone in charge of pastoral care, or as MON suggests a guidance counselor would be perfect).

I feel strongly that there is no place for bullying in school and you need to nip it in the bud before it becomes a big issue.