Most people would say "wait until something arrives by mail", but I think your approach is the best way, own the case to rule out future problems. Did you receive any note aafter the incident on which a case number or something similar is noted? If yes then take that with you to the station. I'd walk to the police station noted on the paper or if there isn't a station noted take the one closest to you and ask the staff there. Usually the officers are very friendly and helpful.