The wattage is controlled by the ballast (or component other than the bulb) so placing a higher wattage bulb won't do much. If you want to get better results you would need to upgrade the lighting system completely or double the amount of light type you have now.
Either a
PC hood or retrofit would be your best bet. There are also powerquad
PC's that might fit well on a 10
gal. What's the tank length?
Cheers
Steve