Many PC audio editing applications will do this for you right on the screen in their parametric EQs. Here's a screen shot from emagic's Logic Audio:
But you have to understand that EQs must be adjusted in real time using your ears as the gude, not hard numbers. The only time a PC will help you in adjusting the empeg's EQ is if you're using a spectrum analyzer.
Trying to pre-program a "curve" in the house, then plugging those digits into the car, won't do you any good. You have to HEAR the changes in the actual environment, and it has to be in real time.
Try looking up threads on "RTA" here in the forum and see what you can come up with. I think that's what you're really trying to do.