You have modest goals - take a CAD file and get your mill to cut it. You dont want to become an expert on CAM software - you want parts today. MeshCAM is made for people who just want to make parts now. MeshCAM works with almost every 3D CAD program by opening the two most common 3D file formats, STL and DXF.
Rhino, Solidworks, Autodesk Inventor, Viacad, Blender, Sketchup, Tinkercad, Autocad, Alibre, ZBrush, and many more work perfectly.

http://www.grzsoftware.com/