
JEFF! What ever you do, do not try to get by with the furnace you have. If the heat exhanger is rotted out any, carbon monoxide gases will be let into your home and will kill you. When I was a service tech for Barker's Heating and Cooling (Lennox dealer), we could loose our license for letting a furnace still be used after finding a bad heat exchanger. We would have to disconnect the gas from the furnace and plug it up.
If anything, go to WalMart and purchase a small oil filled radiant heater and a box fan. Set that up in the house with the box fan blowing on low behind it and you will be very comfortable till you decide what you want to do.
As far as my recommendation on a brand, they all are good and bad. Find one that fits your budget and has a good warranty. I've seen a Chrysler furnace last 42 years and seen a Carrier last a month.
And there are a lot of units that are exactly the same and made by a single manufacturer, but have different brand names on them.
Most all units have the same internal parts. Like AC units, the compressors are ussually Copeland or Tecumpsi (speeling?). The only manufacturer that I know of that makes theier own compressor is Lennox.
Do your homework. Look at the pics, you might see the same unit being sold be two or more different brands. Go with the cheaper one, you'll get the same unit.
Hope something here will help you. Be safe Jeff.