That *might* be ok for the axes, but is definitely not strong enough for the extruder. My extruder motor has 5 kg*cm of torque, but it probably is a bit overkill. Most people seem to recommend 3 kg*cm for the extruder, and 1.5+ for the axes.
You also want a lower voltage motor to work well with the constant current chopper drives that reprap uses, around 3V is good. With a 12V motor the on time would approach 100% causing the chopper frequency to drop into the audio range.
