I think you should go ahead and report it, but I'm wondering if it's happened again since then. Usually abuse gets more frequent over time, and often gets more severe. If this becomes a habit with him, get away from him. Seek out a counsellor, preferably a Women's Shelter counsellor, if it happens again. You don't have to live in an abusive situation.
It makes it difficult to plead your case even though you may have suffered under the hands of this COWARD! The timing is always crucial to report an abuse case...physical evidence is your best tell-tale witness . As you know, by waiting this far along evidence vanishes.
I think that now any judge (if it ever gets that far) may not take it as seriously because you haven't up to this point. He may even go as far as being upset with you for not reporting it a year ago!
Unfortunately, by procrastinating you just may have let the COWARD get away with it!