Sorry to hear that. But if you leave it at 65 you're going to keep paying a lot.

I think someone recommended a space heater... that would be a good way to keep the house lower but the space you're occupying comfortable.

A programmable thermostat of some sort would probably be optimal so you can keep it lower at night/when you aren't home.

They make plastic sheets to help seal windows further. It's going to get worse as January and February Temps roll through.