Easy Boy, you're getting into some deep territory.
First you will need a true 3D cad-cam system that can produce surfaced or solid models and be able to put toolpaths on the models. Something like MasterCam or Surfcam will set you back about 15K.
Then you need a machine that can do simotaneous 3D interpolation (Run a minimum of 3 axis at the same time.) To avoid gouging and bad surface finish the machine will need to be tight with good backlash compensation. Servo drives are best.
For small stuff (20 x 14 x 6) I would shop for a used Bridgeport or Tree CNC mill with an easy to use control (Anilam or Dynapath)
Your spindle speed will be too low to cut wood effectively so you will need to rig up some sort of high speed spindle.
Add in the cost of carbide tooling and tool holders another 10-20K
Then there's the learning curve.
It takes time to learn how to program and most people will tell you, learn to machine manaually before trying to jump into CNC.
Hope I haven't been too much of a wet blanket.
Mike