i've checked canadian tire and haven't seen it. walmart used to carry yellowish "weather" bulbs a while back.Some people are just putting a yellow overlay over the fog lamps Or you could put 3000K (yellow) HID's in.
I just checked the bulb guide and it says the fog lamps are 9006's. Couldn't you just goto Canadian Tire and get yellow bulbs? 9006 is a pretty common size.
If all fails you can goto one of the Asian malls. They have everything there.
The canadian ones got the clear lens/clear bulbs. not sure if it was trim related. i think 03+ were all yellow lens when they changed it to accept an H3 bulbI think different years of IS300's had different fog lamp bulbs and housings. But I know mine has a yellow lense.
Did you find your yellow bulbs for your IS250?