I was checking out my light and its a GE F20T12 CW. The internet says "20 watt 24" T12 Medium Bi-Pin (G13) Base 4,100K Cool White Ecolux Fluorescent GE Light Bulb"
It looks like fish tank "Plant lights" are mostly T8 or T5. Again the internet (This guy seems to know everything!) says T8 use the same G13 base as a T12 however they use different ballasts.
I don't think you would need to switch to a completely different lams setup. If you aren't getting enough light with your current setup, maybe just try adding another tube. (may not work with your hood).
If you go low-tech (I think it's a good place to start, especially if you are new, as it requires a bit less maintenance), you won't need as much light. I don't know how much, but there should be plenty of info from other peoples set ups as to what sort of lights would get you in the right area (I want to guess that 2 flourescent bulbs should work, but I'm not certain)
A couple options I can think of right now (may not apply to your tank/hood/equipment/etc.)
get a twin bulb light strip to replace your current one
If there is spare glass that you can use, just get another light strip (I think you can get some pretty small/inexpensive 24" flourescent strip lights at Lowes/Home Depot), and put it over the available glass.
Set up something using compact fluorescent bulbs- If you're handy, you might be able to make a replacement for your light strip with 3-4 sockets, and with a reflector of some sort, could probably give you more then enough light (be wary of overheating though)