Welcome. You'll want a fluorescent, but I'm not sure the 11W is the one you want. It will put out a lot more light than the 15W incandescent for sure, but it probably still won't be enough light. I assume your hood has a traditional screw-in light bulb fixture, so you can put in any screw-in compact fluorescent bulb you want to. Assuming you get a spiral compact fluorescent, I'd try to get one that burns about 20W, though it'll be rated as equivalent to a 75W incandescent or something.
By the way, check out http://www.rexgrigg.com while you're doing research. His site should answer a lot of questions regarding planted tanks.
By the way, check out http://www.rexgrigg.com while you're doing research. His site should answer a lot of questions regarding planted tanks.