I concur with KTOA.

In fact, go to the Dog Whisperer website and you can order a video(s) that will greatly help you deal with such situations.

In the meantime, if it were me, I'd have reported the dog to the police and say he attacked me. It is a lie, but it is the only way I know of to legally get the owner to abide by the rules. IMHO, the owner of the unleashed dog obviously hates his dog, or he wouldn't allow it to be out uncontrolled.