That's a no-no. Electric heater on the wall sounds like an accident waiting to happen. Where is the thermostat for the furnace? If downstairs It's going to be hard to get it to come on if you're heating with the wood burner. You could try not using the furnace until bed-time, that should cut your use down 66% assuming you have it on for 8 hours. Takes you down to $6 per day which doesn't sound bad. Can you not burn wood in the upstairs fireplace?