You're on teh right track.
Ou may have missed this FAQ, I think: FAQ: Will <insert PSU model> Power Supply work with my system?
Your CPU draws around 84w all by itself. That's pushihng the envelope, and you'll only have 12w for any other parts that pull 12v (screen, 3.5" HDD, normal-sized DVD drive, etc.) I figure this will come close to, if not overload your M2ATX.
I'd look into a higher-rated PSU (Opus 250w or DSATX) or a CPU with a lower power draw for that motherboard.