West Marine sells a number of kits.
It isn’t a job that you can do in an hour if you want the repair to be invisible. First you have to patch the hole with fiberglass resin or epoxy; next you have to try to match the color of the gel coat. If you don’t care about a perfect finish, you can do it yourself by just patching the hole with fiberglass resin or epoxy and maybe some chopped mat to keep the epoxy from just running thru the hole.
If you want a perfect finish, I’d take it in. Matching gel coat color is an art.