Someone mentioned using epoxy. But at this point in time stick to using the resin type that came with the repair kit.
Epoxy is good but more expensive and once you commit to it then you can't go back to the other type of resin. It is one of those situations where you need to stick to materials that belong to specific product lines of resin, fillers and gel coat that are meant to work together flawlessly.
Just go to Dave White's thread You Can Repair Fiberglass
and stick with his instructions and the materials he says to use. Ask about the temperature range you can use them in as that is important to pay attention to being so far north with cold weather coming on quickly. He may have specific advice on do it now or wait until spring because of the weather. He is good about hand holding with beginners and even does phone conversations and private message instructions