Hi. I have just put together this circuit that has three pushbuttons control an rgb led.
My question is: how do i swap out the low voltage led with a more powerful 3w led?

I tried connecting up just the red cathode from pin 3 using a heavier resistor along with another on my red button (pin 9) but i killed my arduino when i tried to drive it with 12v straight from the + terminal on the arduino. I've since got the led and the 3w led working on the same circuit in parallel on a new board, but im only running 5v. I would like the 3w led to be a lot brighter. Preferably with the smaller led lit up too. I know i need to split the voltages, but where? My primitive brain is giving me an inkling im getting too much current going to ground in the board when i light it up, but im basically dumb. Any ideas?

This is where i am currently. theres a little excess wiring left over from an earlier configuration.

 

Thanks robert. the circuit diagram you sent is actually the one i used to drive the 3w led initially. i tried to incorporate the buttons from my other circuit into that but i i did it wrong and fried an arduino. i will look into transistors as that seems like a good way of keeping the voltages separated. if anyone else has some ideas about how to approach this im all ears.