OK here we go, the blind leading the blind.
You need a Cad application to do the drawing. You need a Cam application to convert the drawing into g code and you need a machine controller appication to use the g code to tell the machine how to move etc. I have gone for TurboCadCam which is an integrated CadCam package, that takes care of the first two, and Mach2 that takes care of the machine control application. The best price you will probably find is USD 395 for TurboCadCam and USD 159 for Mach2 (or version 3 if you prefer). If thats to steep then I don't know. Based on two months of heavy reading this is a highly recommended package with excellent support. For a novice you should not under estimate the value of good support. It's a sharp learning curve, IMO.
Best Regards
Phil