123splat - to replace the 3 in 1 you are going to need:
GP C-12 ESC - Tail Motor
Futaba GY240 Gyro - Tail Motor
GWS ICS-480 ESC - Main Motor

I personally used these, and it was so simple even I could wire it and it worked afterwards (I'm electrically impaired ) probably about 150 bucks out of your wallet though... to me, I tried both the modded CP yesterday and my stock one, even though it's the extra money into the heli, I am very happy with the modded version and the stock one will follow eventually.

by the way, I've seen discussions around about substitutes for the GY240, I haven't seen anything definite, I went with the simple approach.. but you can do a "search" and see what else you can find...