ANOTHER lighting thread - 5 gallon

I have a 5 gal tank that I'm hoping to turn into a planted tank for a single dwarf puffer. I'm looking to heavily plant it so the DP can have an interesting environment, and I want to grow wisteria, hornwort, cabomba, etc that I know need moderate lighting (3ish watts/gallon).

I bought the tank from CL for an excellent price, but am sad to say the hood is only rated for an 8 watt bulb. I want healthy, thriving plants (I'm loving my java fern/anubias in my 10gal with a 20watt bulb). So now I'm looking for a 16" FIXTURE that is rated for at least a 15watt bulb. Where could I find these dimensions? My LFSs are poorly stocked equipment-wise and I'm even having trouble finding any 16" fixtures online.

Even though the glass opening for the light fixture is 16" across, could I buy a 12" hood and use that with a 15 watt bulb? I can't see a problem with this other than perhaps looks... but I'm no expert. Does anyone have any suggestions?

Thanks for the response! I had heard of using clip on lights for tanks. Is there anything in particular I should look for in a clip on light? I've been doing a bit of searching for clip on lights and would I want something like this http://www.amazon.com/Black-Goosene...dp/B0000DI4VB/ref=acc_glance_ktch_ai_-2_5_tit which is rated for a 40 watt bulb... and then just buy a 15 watt fluorescent bulb to go in it? I know about zero about electricity- would it be okay to put a 15 watt light in that particular lamp? Or is there something else I should be looking for?

As far as bulbs go this was the "best" one I found - 15 watt, full spectrum, compact fluorescent bulbs. There are other bulbs that are cheaper that aren't full spectrum but isn't that the best for plants?

http://www.drugstore.com/products/prod.asp?pid=197648&catid=142097&trx=29904&tab=1#1