I have a question with my RGB Header on my PC.

[Whathefrench]

Hi, I have a little project, let me explain:

I want to control an rgb lamp, from an rgb header on my pc but wirelessly.
I’m gonna use ATMega328P chips on both side, and flash an arduino bootloader on it. That way i can use arduino language.

So, I have already design something for the lamp side.

This ATmega328p, just basically receive data through RF, and just control the leds. If nothing is, receive for 30secs, the chip just run a small program, to light up the LEDs following a pattern.
On the pc side, I haven't really done anything yet. How can I power the circuit from the rgb header, and recover the pwm signals from the header at the same time ?
I know the rgb header for pc are common anode, because the header is [+12V,G,R,B]

Thank you in advance for your answer! (Sorry, for my bad level of english, i'm not a native english speaker)