What kind of bulb're you actually using, incandescent, or flurescent?
If it's incandescent, it's the wrong spectrum, gives out more heat than anything else.

Keep the light at no more than a few inches away, save up your money, and as you're new to growing, buy a new 400W HPS bulb, ballast, and reflector.

I assume you're in the states, so I can't convert how much it'll cost, but over here it cost me £85.

Second hand bulbs & ballasts generally aren't a good idea, bulbs have limited life, and with age, the lumens emitted are decreased.

Do some reasearch, get some proper equipment, then try again. I remember growing a spindly sunflower, when I was a kid, didn't thicken up, just flopped over as it couldn't support itself.

If I were you, I'd be tempted to take a cutting of "your healthiest" plant, where the leaf formation is closer, use some hormone rooting powder, and see what you can salvage.

Get a cheap propergator, or put a plastic bag over it, to retain humidity.

Low watt bulbs, like you have, are ok for this purpose, as the plant won't be intesively photosynthesizing, it'll give the plant chance to form a root formation.

Hopefully the plant'd be healthier, and not 2 stretched.