A new mountain to climb

We have a new burden and that would be our central heat and air that is no longer working. Most places want around $3700 and while I had that much earlier in the year it went to get caught up on things like the mortgage. I'd rather be hot in my house than not in my house at all. Financing is pretty much out of the question so any ideas? Ideas and help is appreciated. :) Oh how I miss 2007-2008 when the economy was at my favor. On hindsight, should have fixed it then.