Had the same problem and had a few good suggestions from here. But decide on a product called seal-all
Seal-All 050307
I used automotive panel push pins (the thicker plastic ones with ridges so they won't pull out). I coated the push pin with the seal-all, pushed them in the holes then layered the seal-all over the top over a few days.
I've had gas sitting back in the tank for a while now with no leaks. Of course i haven't tested it in the winter, but this repair looks great. I'm not worried at all.