I'm into plasma cutting but would one day like to cnc retrofit my "Bridgeport" mill. For cheap CAD you can't beat the personal edition of Alibre Design. This opened up the world of 3D cad for me while on a limited budget. I'd guess the price is around $150 for the personal edition, then $800 for the Professional Edition. The best prices I have seen are from an Australian reseller called CADDIT, google them to find their website.
As for CAM there is sheetcam which is 2.5D so I think it can only do vertical z-axis movements.
Both the above have good support forums. Alibre have cam included with their most expensive version - Alibre Expert but you might be getting close to the $2k mark for that one so if sheetcam will do what you need then I think it's more around the $200 mark. Alibre also have separate cam packages but I don't know if there pricing is outside your budget.
Hope this helps a bit.