If it's that steep, you might consider building a stairway along the side of the driveway from top to bottom. There's little that can affordably resolve your problem with the driveway itself. If simply walking down the driveway will present problems, think about those times when your hands are full of groceries, etc.

Are you in Hawaii? Or just dreamin of being in Kauai? If so you aren't worried about ice. If you can't afford the stairs like treebeard suggested, what about a paint. I think they sell something with a grit in it and you could probably get it in any color to match the driveway. You may want to post under the subject paint if this is a possible solution.

Just an idea,

Devildog