This thread is hilarious. I love it when kids feel like they're invincible - regardless of what happens, make sure you keep that part of you alive.
Back to reality though - the facts are:
1. You claim to be a smart computer person, the go to person to fix things - yet you can't fix your own computer. Honestly, your problems sound like it can easily be fixable by doing a complete reload of Windows OS. If money really is an issue and you NEED a computer to work, you will do what you have to do to keep that one going forever.
2. I personally don't care about the fact that you're 14. I've worked with amazingly talented 12 year olds who can program asp.net around me. I also know and have heard of great teen entrepreneurs who make millions off of great ideas. Unfortunately, from your posts, it doesn't seem like you are a mature 14, but rather, just an average one. So despite what you believe about yourself, you're really not that that different from a typical teen who wants the world and thinks the world owes it to them.
3. Most businesses justify their purchases based off of ROI. If you want a $3000 computer at a job, many would have to justify how that purchase would result in the business making more than $3000 in return. In your case, if this new computer can help you make more than what you spend, the decision should be a no brainer. Go get that computer now. If you can't justify it, maybe consider that you only WANT this thing and do not NEED it.
Just because Apple chooses to release new shiny objects every 10 months doesn't mean the previous models will shut down and die instantly. While things may take a few seconds more, any of the unibody MBP's will be able to do exactly what the new one does without any problems. A mature person would realize that just as a mature person with financial issues would buy a used car instead of a new one. (Or take public transportation if vehicle ownership is too costly.)
Anyway, I don't mean to preach but the world owes you nothing kid. While one may want the shiniest MBP today to last through the rest of high school and college, let's face it, once the next new one comes out you'll be setting your eyes on it. Why not get something that will get you through the next year or two - learn some new skills, make some real money and if things change for the better in two years, get the newest one then. Nothing in life is permanent and money will come and go. Get what you can manage to afford today and move on to the next target. By having your heart set on the highest end model and possibly going into debt for it, the only person you are helping here is Steve Jobs, not yourself.