If you want a light with visual light use the Exo Terra 75% concentrated basking bulb. Now this must be used with a dimmer switch and will warm the enclosure without being run at full output. It is safe for the frog as long as you do not run it at full power. They are very efficient and I use them myself. They last a long time. Anytime your tank warms up humidity will fall with the rise of the temp.

If you don't want visual light go with the CHE Digitalpunk mentioned. Make sure they are no higher than 50 watts.