well wolfn the size of area will be best suited with this bulb http://homeharvest.com/hydrofarmcompactfluorescents.htm
The compact flourescent bulbs are probably your best bet. That one there in particular has the k rating and lumens of nearly 8500 wich should be plenty for what you have.
I am getting a 100w led from ebay to light my terrarium. Anybody tried this?