Well, if you just want to learn how to use Mach Studio PRO, then a gaming card would be enough instead of having to buy a workstation video card. However, it seems the program will rely on the video card for some of rendering. Therefore, the question is how much money are you willing to spend.
The HD 5450 I recommend would work with the program, but it's graphics processing ability is rather limited so your rending time will be slow. While a DX11 video card with 2GB of RAM is recommended, you can get away with 1GB. So it basically goes back to how much money are you willing to spend?
As for a CPU recommendation, the easy answer would be the Core i5-2500k. But it all depends on your budget.