Im completely against under-tank heating for arboreal frogs..
These guys live in the shrub layer so Im sure others may differ in there opinion..
The American Green tree frog requires a Temp range is 68-77F during the summer, and a little cooler in the winter.. So Your household temperature should almost be good enough..
That being said..
You need a Thermometer if you dont already have one..
I like the hood.. yes 10-15 watts would be better.. but I dont think incandescent lighting is the way to go.. A nice low watt compact florescent would work much better in my opinion.