I would search cold weather epoxies online and see what you find. I don't think I would want to get into such specialized epoxies though. If you don't think you'll be able to bring the work surface and area up to temperature, it would be best to wait till you could. You could do all the prep work now, then on the first warm weekend in spring, epoxy. You wouldn't have to wait till the weather is warm enough to epoxy. You'd be waiting for it to get warm enough that you could heat the area enough. If it is getting into the sixties during the day and staying above the high forties at night, you could probably heat the work with your propane heater and a tarp over the area. It's over coming freezing temperatures at night, and barely making it to forty during the day that makes it to difficult to try right now.
!! WARNING !! The above information is to be used by intelligent people only. If you are Stupid, could be considered a moron, or otherwise. You are instructed to disregard this information and seek the help of a licensed and bonded professional.