You might find a free manual here: http://bit.ly/autozone_repair_info or go to http://bit.ly/alldata_repair_manuals or http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.
I'd not be too sure that it is exclusively a thermostat problem . Is your antifreeze reservoir up to the full mark , & does the engine temp gauge register up to operating temp ? or is it down on the cold side ? If it registers on the cooler side of the gauge & the fluid is low you may have an antifreeze leak - perhaps the heater core if the windows are fogging .