CNC Plasma Help

I have a use for a CNC plasma and need help. This is all brand new to me. I have the machinery necessary to build the mechanical end but the CNC computer end is beyond my current knowledge. I have very little electronic knowledge. From the research I have done I found this list and I am gathering info daily. I guess the real help is needed right now in figuring out do I need servo motors or stepper motors, ball screws or gear and rack assembly, which software should I try to use since I want to import bitmaps. The goal is to be able to cut up to say 3/16" steel plate with a imported line drawing with fine details. Like a shadow cut to be made into signs. I think the largest field I will need will be 4' X 4'. My shop is pretty complete I have a Bridgeport, 15" swing lathe, mid size turret lathe, universal tool and cutter grinder, MIG TIG and Stick welding machines and Oxy/Ace pantograph shape cutter. None currently CNC all Manual.
Any help at all is appreciated.

Thanks Don Robertson
dnrobert@...