Part# for the light bulb does not exist. Basically, just go to your favorite auto parts store & look at pretty much "any" brand that has the H3 type bulb available. Prices can vary, you can find H3's for as less as $6.00, or as expensive as $33.00 for a new H3 bulb from the Toyota dealer (YIKES!!!!!). I paid $27.00 each for mine (because I bought the amber/yellow colored bulbs from PIAA, rather than white's or super white's (which I did not want)).
Personally, I would not get 100W bulbs, our electrical wiring for the fogs is not up to the task of handling them, considering that the fogs were originally 55W bulbs. You might be able to get away w/ 85W bulbs, but 100W bulbs will be pushing the system