I would read Alan Vaitses book on Fiberglass boat repair. It's not the big of a book, but it'll give you a strong foundation for doing your own repairs. Surface prep is just as, if not more, important than making the actual repair. I would patch it "ugly" (meaning that it doesn't have to be perfectly smooth) and install a keelguard/keelshield.
http://www.keelshield.com
This would aesthetically finish the repair and you would protect the keel from further damage. My boat's keel has been patched up by a previous owner and this is the way I'm going.
FWIW...YMMV