PS2 Controller Mod

ok i got a PS2 controller i dont really use n e more and i wanted to mod it with Loads of stuff, and one thing i got 2day is some LEDs to install in them to make it light up. and idk how to install them in my controller to make them work??? bcuz i want to on the back of the controller next to the L1 and L2 and R1 and R2...like

L1 | (LED) (LED) |R1
L2 |____________|R2

so ever time i press a button on the left side, the left LED lights up...same for the Right side...i would i install them???? where would i solder them or w/e?

one more thing how would i install a 555 Timer chip, mosfet and Led Flasher Curcuit and where to get them???

srry for all the questions and thx much appriciated