Hi scotty,

Welcome to the forum. Have you got any pictures of the machine you've bought? I'm guessing that because you're thinking of upgrading it, that the BBC computer isn't working?

You need to work backwards from the motors. Steppers or servos? (steppers probably have 4 or 8 equally sized wires going to them, whereas servos will have 2 fatter wires and 4 or so much smaller wires).
The motor type decides what controller to buy. Which controller are you thinking of?
Once the controllers are decided you need to wire it up to a PC.
The PC then runs software like Mach3 (not free but well-documented), or EMC (free, and getting simpler by the day).

I hope this helps - it would be great to see some pics...