First off, the qualities that make a good fog light make for a bad driving light. The purpose of the fog light is to help you find the edge of the road in heavy fog. That means a light mounted low with a wide beam and a sharp top cutoff so that it doesn't blind you in the fog.
Instead, start off by checking the aim of your lights and making sure the lenses are in good shape. If you have old plastic lenses that are yellowed and/or scratched you could try a polishing kit or look for glass replacements. The stock lights are decent, especially with good bulbs. You want even light distribution down the road – not a bright spot close to you, that causes too much contrast and makes distant objects harder to see.
If you can it wouldn't be a bad idea to also check the voltage getting to the bulbs, it is possible that your light output is low due to resistance in the circuit somewhere.