Help Me!

My 1992 Geo Metro's headlights will not shut off. It has one of those twisty knobs (real intelligent wording) instead of the push/pull knobs and the knobs will turn all the way around without doing anything. I have to disconnect my battery everytime I leave my car to keep from the battery going dead. I do not have the money to fix this problem professionally, I would like to know if anyone would know how to fix it.
Thank you
MetroManic

Is it the knob on the steering column? The knob at the end of the turn signal lever? If so, go grab one from the junkyard. All you have to do it pull the center cap off the steering wheel, take the nut off the center of the steering wheel, punch the wheel a few times to break it loose, and all the innards of the column are right there. You might have to take the cover off the column to get at the innards. Your problem isn't all that un-common.