Heat Pumps and Electric Heating - how do i decypher what the size

of my gas pack unit. It is a RUUD gas pack the model # is URGG-10E37JKR. It says on the name plate that the heat is 97000 btu, but i can't find anything about the cooling. The unit is 16 yrs old, and the burners have burned out and also the wires had burned off at the compressor and had to be worked on 2 times during that time. It always put out air that really cold but would run for only a few minutes and get the temp down but still felt humid. So i wonder maybe if the unit was over-sized to start with. If so i plan on down sizing by a half ton, and replacing it with a heat pump. I live in a 2 story house and this unit is for the downstairs. I live in south eastern nc and the coldest days are rarely below 15 degrees( may 4 or 5 times this winter and only in the early am. but most of the time the average is 40 or higher. The downstairs is about 1260 sq ft with 2 sets of stairs....Also if i replace with a heat pump will i need any additiona wiring with either a 10 or 15 kw heat strip.....sorry for being so long..thanks

would really appreciate any reply to this to help me evaluate what would be the best way to go on a new and possibly different unit....thanks again