Controlling a stepper with EasyDriver externally

Hi guys, I need some help here. I apologize for my ignorance, but my knowledge is limited.

I work for a theatre company in Houston, TX and I'd really like to bring more sophisticated and DIY style control into the work we do. Unfortunately I'm still a virtual novice at this but I'm trying to learn.

Right now we have a show that needs a specific effect. In order to make it work, I'm trying to drive my stepper motor (the ubiquitous SparkFun stepper) with an Arduino and EasyDriver. What I really need to be able to do is control the motor externally with a switch and potentiometer.

I would like to be able to set a speed with a potentiometer and flip a 3 position toggle switch to run the motor either forward or backwards to a pre-programmed position. Once it hits the position, the motor should stop and hold until I flip the toggles switch to tell it to go back.

I know I'm asking a lot, but does anybody have ideas or examples of code and/or set-up schematics for making this happen?

I'll buy the beers next time you're in Houston and take you to see a really great show.