The same site offers a lot of goodies online:
mh-audio.nl - Home
IIRC, this is the QRD calculator that's in the program:
mh-audio.nl - Home
This one is slightly different in the input parameters, giving more control:
mh-audio.nl - Home
If you wan't to go 2D, you're better off using a real calculator, like this one:
Calculate a Two-Dimensional Primitive Root Diffuser (Skyline) - the one in MH-softs program is way simplified compared to what the real values are.