You could do 1 of 2 things.
First thing would be to go with an HID conversion kit. Those can be found anywhere online. Ebay has some, and I've heard that
XenonDepot is a good company from the Lexus forums.
Second, you could go with some Hoen
Xenon Math Plus bulbs. I've heard good things about them and the pictures on their website look good. There obviously other brands out there, i.e. Silverstar, which you could pick up from any autoparts store.