I had this problem on my last Jetta, and I used a rather unscientific method to correct it:
Park car next to a wall, start car and turn on headlights, open hood, adjust headlights in desired direction using screws on top of the headlight housings. Close hood, get in car, and drive around the block to check light pattern (at night obviously). Return to wall and re-adjust if necessary. Keep doing this until you get it right. It helps if you have some reference on the wall, siding worked well for me, so I could aim between the lines.
It took me about 45 minutes with crappy tools and very little light to work with. Everyone in my apartment complex must have thought I was a nut, driving in circles over and over!