I have a Prius C 2 so it has the headlights but no driving/fog lights. Is it just me or do the headlights tend not to light up a lot?
If you don't want to go the HID route (ballasts, rewiring, etc.), you can install modified 65w halogen H9 bulbs (link in my signature below). The H9 mod will give you approximately 50% more light over the 55w H11 bulbs that are standard.
Don't worry much about fog lights. They just light up the sides and a little right in front of you. You get a good shot of people's trash cans as you drive past. Not much good if there isn't any fog. Couldn't tell you anything about a C2's headlights. I have the C4. They aren't too bad. I've had worse. I had to point them a little higher than the way they came. The cutoff just wasn't doing it for me...wasn't lighting up many signs or roadway.
There is an adjustment bolt/screw in the back of the headlight housing. You can turn it with a socket wrench or with a Philips screwdriver.