No heat Climatronic code is 4FA and 538

My heater worked last year fine we let the car sit for about three months and during the summer. The AC did not blow out cold air. The compressor is bad but the heater was still working, but now all I get coming out of all the vents is cool air. It feels like the air from the outside temperature really so I did the climatronic system test and got codes 4FA and 538. I also did the "reset" test where it cycles through the whole climatronic system to test everything to make sure the code was right and sure enough it popped up again 4FA. I can hear the motor clicking to open/close the flap when I switch the temperature from cold to heat but still only get cold air coming through vents. I know it is really hard to replace the motor that controls these flaps so is there anything else I can do? I have a three year old and this is our only car he already had to deal with no AC all summer (cannot afford $400.00 for parts and $300.00 in labor) with the windows always down. But, I cannot let my little guy freeze all winter. Please help I need to fix ASAP! Thank you in advance!