The computer you have is probably good enough. However, if you want a new one, here are a few suggestions:
1) Don't call the 2 TB part "memory"; it's hard drive space. RAM is memory (Random Access Memory). Just a little technicality...
2) Why do you "need" this computer that has a 2TB HDD and 8GB of RAM? You'll need that if you're running every application on the Adobe Suite, Maya, 3DS max, and Fallout 3 at the same time...along with storing 2,000 GB of information. A 500GB hard drive is plenty, unless you're doing a LOT of work (which, no offense, I doubt you're doing at 12 years of age). Even if you are doing a ton of work that needs a lot of space, a 750 GB is fine for that.
3) Building a computer doesn't have to cost 7 grand; in fact, it generally costs less than a store-bought computer. If you want to build your own (which I recommend), you can use Google to learn how and newegg.com to buy parts. The eggxpert chat from newegg is a good place to ask questions. This is probably the cheapest option.
4) Get a source of revenue. Seriously. Find some way to make money: mow the lawn, wash cars, babysit. If you really want this, barely anything should be considered beneath your dignity, and I mean that. That's how I made the money to buy my guitar, the Adobe production premium suite, and nearly everything else I own. It works. I know it's hard to get a job at 12, but look around for one.
5) Why do you need such a "crapload of processing power"? The type of hacking you're going to be doing for the next, oh, seven years won't require such amounts of processing power, unless you're a genius at this already. However, if you were, you wouldn't really be asking us about a computer.
Basically, cut corners where you can. I would suggest a computer with 300 - 500 GB of hard drive space, 2 - 4 GB of RAM, a decent graphics card, and at least a 2 GHz dual core processor. You really don't need 2TB of space. Believe me, unless you're saving a TON of stuff, and by a ton, I really mean "a ton". (get it? 2,000...oh, whatever)
Mens et manus.