Need Help Selecting CAM Software

I have just finished building a 3 axis, stepper actuated, gantry
style router table. I am a model builder and my short term goal is
to be able to cut 2D shapes such as wing ribs and fuselage
bulkheads. Long term, I am learning Rhino 3D and eventually hope to
produce 3D objects for vacuum forming and fiberglass molds such as
canopies, cowls, fuselages, etc.
I am well versed in 2D CAD, dangerous with 3D and I don't have a
clue when it comes to CAM. I am looking for recommendations for a
reasonably priced (preferably cheap) easy to learn CAM package that
will accept my existing AutoCAD or dxf files. Maybe "cheap"
and "easy to learn" don't go together, so a reasonable compromise
may have to do.