2 questions for you all.
 

Do I need a professional speaker for my editing. I have speakers set with a sub-woofer that cost $40.00 and sound great but then I saw set of speakers in guitar center for editing and thought to my self do i need it?
most of my work is wedding.

question #2
while editing how dim is the light in the room if dim at all?

Good studio monitors are not a bad idea, but you can probably get by using a decent pair of headphones to check your audio for subtle flaws. Your computer speakers are probably close to what your final viewing environment will be like for your audience, so they actually aren't a bad thing. If you have the money, a quality set of studio monitors are worth the price and will hold their value, but you should still check things out with headphones and a setup similar to what your audience will use.

I would strike a happy medium with the light level in your room. Dim it a bit to make the computer the center of your focus but keep it high enough to keep your office functional. Perhaps more important than the light level is the color. You should probably not have really bright color schemes near your edit station that could shift your color perception. Again, you should also check your color correction out on more than one monitor even if your studio is correct. If it looks great on a color-perfect monitor but bland in people's living rooms, you may want to compensate.