Layered clothes. Head, feet, and hands. A lot of heat escapes through your head. Need to wear a hat and warm socks. Wool is best. Wicks moisture away from your body.
Wool socks and warm slippers will help a lot.

Wool, down, or good fleece blankets and/or outerwear will keep you as toasty as any electric blanket.

If you're planning on using your gas stove for baking, you might want to unplug your stove and try to light the pilot. Some stoves that use a ugh, piazo? to light the burner, won't work without electricity.

A good lamp will put off a lot of heat. LOTS of heat. Have to be careful about fire, but it offers much heat and comfort.

Good luck. Stay safe and warm.