So I bought a gaming PC down in October of 2008, and as of yet I have not upgraded the internal components. I just had a price range, and had someone build a PC for me within that range. Since then I have learned more things about the internal components of a PC, but I'm having trouble now with upgrading. I know I need a GPU and a RAM upgrade mainly, but if thats the case, I will probably need to buy a new motherboard and power supply as well. So my question is, where do I start, do I search for the GPU i want and then choose the the other parts around that, or what? Any help would be appreciated. Also, I have read the sticky guide on building your own PC, but it's for builds from the ground up, and didn't find it all that helpful(however its great for newcomers and people building new builds.

How out of date is your CPU? Your GPU is obviously the most important part, but if you're buying a super badass GPU and have a terribly old CPU, then it's like strapping a hydrogen bomb on a biplane.
 
If you're happy with your current CPU, I'd start by maxing out your systems ram and see how much a difference that makes. If you're still not happy, then spring for a new video card. 
 
Like I say, make sure you're happy with your CPU, then build up from that. Max out ram, pick a GPU, determine it's power needs, buy a matching P/S.
I have a Core 2 Quad and I find I have to push it pretty hard at 1920x1200 for ultra quality. YMMV depending on what GPU you pick.

It depends on what your issues and problems are.  Without having run dxdiag on your computer, I don't know what you have, and I don't know what sorts of games you want to play.  I got a computer in the same general era, so I can tell you what I'd do.

I bought a stock computer from Best Buy (Note:  Never buy the service agreement unless you are 100% confident that you will both be willing and able to use it -- it's horribly overpriced.  Buy a geek friend dinner when your computer breaks -- it saves money).  It came with 8 gigs of RAM, Windows VISTA, 688 Gigs of hard drive, and an ATI Radeon HD 3200 for graphics.  I have an AMD Phenom 9500 Quad-core processor with 2.2 GHz processor speed.  Don't worry if that doesn't all make sense to you, it doesn't to me either.

I think my processor and RAM are pretty decent, if not top-of-the-line anymore.  I've just about filled my hard drive (only 115 gigs of space left), and I frequently find that intense graphic options are too much for my computer.

I have pretty sucky graphics options (ATI Radeon HD 3200 is an integrated chip, if I understand right).  That'd be the first thing I upgrade on my computer, because increasingly the games I want to play require more intense graphics.  (In fact, what I do or do not buy is being dictated by whether I can run it on this thing or not).  I'd either upgrade this, or save the money and just buy a new computer (leaving me with a backup old computer).  I'm also looking at getting an external hard drive.

To upgrade your computer, you just need to figure out what you don't have.  More RAM lets you do more at once, and can make the difference if your computer doesn't like things like big maps in games.  If your problem is more "Whenever there's a waterfall on the screen, my system hangs up" the issue is probably graphical.  If nothing else, you can print out your dxdiag report and get someone in a store to help (that'd be my last resort, though.  Try for someone you trust first.)

Simple answer: you always start with the CPU.
 
For us to help you better, you need to give us your exact specs.

I will when I get home. Thanks for the help so far guys.

K my specs:
 
Motherboard: Wolfdale1333-D667, 2 PCI slots, max ram capacity of 4096 MB. 
CPU:Intel Core 2 Dup E8500, 3.16 GHZ
GPU:Nvidia GeForce 8800 GT
2 GB of DDR2 Ram(Micron Technology)

Actually for a start invest on a very good motherboard cause from there the performance of all your other hardware especially your CPU and GPU will matter. And don't forget to also invest heavily on good power supply units. You wouldn't want some of your hardware to fall short on electric distribution cause I tell you that will really be a bummer. 
 
Since you use intel processors I'd recommend you get the ASUS Maximus III Extreme. The only setback is that you will have to also replace your current CPU with an i5 or i7 as I don't think this mobo supports Core 2 Duo series anymore. Though another option to retain your current CPU with good performance is if you can still find the ASUS Commando Motherboard. 
 
As for your Power Supply I'd recommend going for atleast 1000W and ONLY get reliable brands like Enermax or Corsair. 
 
Hope that helps. :)

Cpu is acceptable for games that aren't quad core related like gta 4, assassin's creed 2, red faction gureilla ect which will cause stuttering. Everything else should be okay. Maybe just add another 2 gigs of ram and a better gpu. I mean you want to play more games better right? Even a gpu upgrade to something better should see some results. I mean you don't have to throw everything away and start all over, money doesn't grow on trees, just upgrade the gpu first at least and if loading is too slow, add more ram.

" K my specs:  Motherboard: Wolfdale1333-D667, 2 PCI slots, max ram capacity of 4096 MB.  CPU:Intel Core 2 Dup E8500, 3.16 GHZ GPU:Nvidia GeForce 8800 GT 2 GB of DDR2 Ram(Micron Technology) "

• Motherboard as that board only supports up to Core2Quad Q6660.  Even if you stay Intel the current CPUs use different sockets. 
  
• RAM as any board you purchase to match the new CPU will need DDR3 type RAM and yours won't be compatible regardless of whether you go Intel or AMD.
  

" K my specs:  Motherboard: Wolfdale1333-D667, 2 PCI slots, max ram capacity of 4096 MB.  CPU:Intel Core 2 Dup E8500, 3.16 GHZ GPU:Nvidia GeForce 8800 GT 2 GB of DDR2 Ram(Micron Technology) "