Yup - sometimes you gotta step up 'yer game.  And it's certainly worthwhile to try something a little more drastic before just replacing.  Always a good idea to start less aggressive first, though, Goose.
One tip, for the future... regular cleaning and use of a protectant (like 303) will help to keep the mold from coming back.  Mold is MUCH less likely to grow on a clean surface.  On my Grady, I get mold on some of the fiberglass because I don't wax it or clean it that often.  It's more of a "workboat", though.  On other boats that I have, I keep them waxed much better and I never get mold on the fiberglass (or the vinyl, for that matter).  Some of this comes down to environmental conditions, as well.