Are you paying by the kh for your electricity, or are you paying a flat monthly fee for electricity? If you are paying a flat fee, you should get a couple of small electric heaters--700-1400 amps--and use them to cut down propane use. If you are paying by the kh, it is going to be expensive to run the heaters.
I would stay away from anything that has a flame, such as a pellet stove, because of the danger of fire in such a small place.
Also, living in northern KY may be warmer than southern KY, which is why people are asking for more details. Living in the mountains is obviously going to be really cold.