What is the length of your tank? 36" or 24"? Bulbs come in set amounts of light, meaning that a 24" bulb will only be 20W, or a 36" bulb will only be 30W, and a 48" bulb will only be 40", although there are exceptions. So yea, it's hard to increase lighting unless you get another bulb in there, or use power compacts. In both cases, I'm sure you'll find the solution not toyour liking as you'll have to add a bulb or two.
Anyway, lighting depends on what kind of plants you want to grow. If you're going high light, you're going to need CO2 and a fertilizing regime. Are you prepared for that?
And just read it, watts per gallon... So, watts divided by gallons.
Also, why would you want to use SW bulbs for a FW tank? It produces more light at the blue spectrum, which plants don't really use, so algae will gain the upper hand...
Incandescent bulbs are the type you screw in, and is commonly used in houses. It produces a lot of heat though, and for most of them, the kelvin rating is lower than 6000K, which is the best for plants.
Please read all the pinned topics on here if you're serious about going planted, and then you'll find it a lot easier to grasp the basic concepts and you'll have a better understanding of what you want to acheive, and what you need to acheive it.
And no matter how old you are, in my eyes, there is no excuse for lack of proper punctuation, grammar and spelling.
Cheers,