You could always go with another Coleman type unit, but those are expensive. Many people on here myself included have switched over to an inexpensive digital thermostat. I bought a cheap non programmable thermostat at Walmart and it runs on AAA batteries and it does the job well. But mine only controls the heat.
As said above these thermostats do not have a low and high fan speed. Some people just wire them on high fan and some add a micro switch to the side of the thermostat to control the fan speed. There are a few write ups here and on the net to help with the wiring.
Link to digital thermostatLink to one of many posts about wiring.