What wattage light are you using? I'd recommend a 45-50 watt halogen flood (infrared, not the fake infrared incandescent bulbs). They're pretty inexpensive, or a Ceramic Heat Emitter with a rheostat (adjuster for power). If you put it on one side of the tank your frog will self regulate by moving to cooler/warmer areas. Misting a couple times a day will keep your humidity at a good level.

Not trying to be a dick, but if it becomes too much of a hassle and you can't afford him I'll buy him from ya depending on what he is. Others would take him off your hands too. Again not being a rude a$$, just trying to help you out if you need it.