I agree with Chris in that trooping and being a part of the 501st has been a blast, and an experience that has added a wonderful dimension to my life. I've made friends all over the world, brought joy to countless people, and gotten to live my Star Wars dreams. However, this is a hobby and school is partly about preparing for the future.
A good rule of thumb I've heard when buying computers is to buy as much capability as you can afford, because the cheaper and less capable you buy, the more quickly it becomes obsolete. As for your computer studies, although it really depends on exactly what you'll be doing, it's better to have an overpowered machine and be able to grow into it than an underpowered machine and quickly outgrow it.
It sounds like you've been a very responsible young man, what with attending and paying for school, paying for your car, etc. Good for you, continue to do so. If you can afford both the good computer and the AP kit, great! Otherwise, take care of you educational requirements first. We'll still be here, I guarantee it.