I'm not that far away from you, you can wrap the tank with a blanket to insulate it and use a battery powered air pump and a stone. The good thing is it's a betta they can tolerate higher temperatures, if the tank gets to hot a small soda bottle that's frozen can lower the temps for you. I have a pair of generators at the house the small one I can setup to power the filters on 3 tanks and 2 chiller units.
I do not have an air stone/pump I am more worried about the cycle for the tank is there anything I need to do for the filter specifically, like do something with the cartridge or nk