Any chance you could go on budget billing with your power company? I did that and it spaces the payments equally over a year rather than spiking them in the winter and dropping some in the summer if I don't use the AC as much. As far as a more efficient heating method, I can't help you there, sorry. I have baseboard heaters in my snake room and keep an oil filled heater close to the racks with a fan blowing over it to keep things nice and toasty in there.
How large is the room you're trying to heat? Any chance you could reduce the size of the room or move your animals into a closet or something so the heater isn't working as hard/pulling as much electricity to heat such a large area? Fans might help too, especially if you can get them off the ground to help pull the heated air back from the ceiling and down into the room/floor level.