How do you folks feel about wool sweaters? Other than being a little itchy the only real maintenance that you need to be concerned with is an occasional dry cleaning and a little mending now and then. A real plus here too is that a sweater is very energy efficient and repair parts are readily available. (Note: Some rhinestone buttons may be difficult to match). Furthermore, most sweaters are clean-burning and don't leave the smoke and other residue that are characteristic with most conventional heating systems.
If the sweater idea simply doesn't appeal to you than may we suggest that you consider a gas-fired forced air furnace. Unlike your current wall furnace a forced air furnace will distribute the heated air to all areas of the home via a comprehensive network of ducting. Typically the heating contractor will design and layout the heating system so as to maximize the efficiency of the unit as it relates to the size of the home, the number of rooms, and the relative size of each room.
An added bonus for you with this type of system would be the addition of an electronic air cleaning system which will remove dust and dirt particles from the air.