is it furnace,blower,or packaged central

where are all units located?  do you have an attic?

see, i'm not an ac guy, but i already have so many questions. btw, different areas may have different style of ac installation.

even a well trained ac guy stilled have to climb up your attic, take a look, and than can tell you what kind of option you may have.

go find an ac guy to check, than ask for options and price, etc.