First off, if you clean up the area around your treadmill and put a boombox or TV and some posters around it will give you motivation. I know that when I have a dusty mess around my workout equipment, I tend to dread using it, but once I clean up and make the area a little more fun, I don't mind as much.
For the step, if you try to do the moves and when you get too winded just go back to doing the right and left basic steps, you will build up your endurance and eventually be able to do more and more of the kick butt moves that are hard.