How can I find this LEDS
 

Hello I want replace the LEDS of my head lights, how can I find the four leds that goes under the main lights?, thank you.

Spyder® 444-TTC04-HL-AM-BK - Scion tC 2005-2007 Black Halo Projector Headlights with LEDs

You aren't going to find LEDs specifically for that headlight. You'll have to buy LEDs that you can solder in.