Ultrasonic sensor + 5 high power leds

Hi! I need help with an art installation.
I want to use an ultrasonic sensor to turn on and off 5 leds (the leds turns on as you approach the sensor).

I already have the programming and it works with low power leds but I want to use high power leds and I don´t know how to make the circuit.

My leds are 1w so they need like 300Ma. I want to use external power. 12 volts from a ac/dc converter.

Do you have any idea how the circuit would work with the external power?
Thanks!

Sure, use a high power LED driver.