Question about these "replacement" fluorescent bulbs?

Bought a couple of canister lights. Kinda like a floor accent light. Takes a 50W maximum bulb. I bought a "50W" bulb that I thought was a regular incandescent floodlight bulb. As it turns out is is one of those fluorescent replacement bulbs that only uses 11 watts of power. Its not nearly bright enough. Could I use a much higher wattage fluorescent replacement bulb since this one only uses 11 watts of power?