insulate the room properly before buying a heat source. Invest on good block drafts, heavy curtains, large soft comfy rugs for living room, and try to set-up a large tent inside to trap heat. Do everything just to prevent heat from coming out your home, conserve warmth before choosing a heater.
Now, for your situation, especially that winter is nearing, I think your best bet is to buy propane or kerosene. Just don’t forget to buy some back up batts, extra cannisters, good CO detector, and fire extinguisher for emergencies.