ultra-low budget gaming PC

[Eclipse]

After a little bit of research i've figured out that my current PC is in no way capable of playing PS2 at anything resembling decent settings. Unfortunately, my current budget to upgrade is practically non-existent, which leaves me in a bit of trouble.

However, i am working towards scrounging up some funds, and was wondering if anyone could give me some pointers on the cheapest way to achieve (theoretically, since beta's not even open yet) a machine capable of at the very least getting PS2 to function at minimum settings.

A little bit of digging has given me a few suggestions, namely the Radeon HD 5670 or Radeon HD 6670 (~$65) and the Pentium G630 (~$70) for a GPU and CPU respectively.

The component i have the biggest worry about is the motherboard, simply because i have absolutely no idea what all the technical jargon means and whether i'll need any of it for a very simple, cheap, bare-bones gaming rig.

The RAM, PSU, hard drive, case and screen are all important, of course, but again i have absolutely no idea what i can get away with if i'm building a PC almost -purely- for playing Planetside 2 at the lowest possible cost.

If anyone could give me advice on budget parts, overclocking and money-saving tips, as well as possibly explain some of the techno-mumbo-jumbo surrounding PC components i would be VERY grateful.

i apologize for being such a noob about this kind of thing, by the way.

[EDIT]

i stupidly forgot to put this in. Oh well, that's what the edit button is for i suppose.

1. Are you building this computer yourself or having one built for you (Like HP, Alienware, or even a small shop)?
Building it myself

2. What is your budget and does that include shipping/taxes?
As low as possible... probably $100-$300, and that's a long shot.

3. Where do you live (Please list town, state, and country)?
White Plains, Maryland, USA.

4. What do you need this computer to do (like gaming, Photoshop, and so on)?
Pretty much only play Planetside 2.

5. What parts will you need for the computer? List what parts specifically, saying you need everything will not do.
Most important part is the GPU, then Motherboard, CPU, RAM, PSU and i guess a new case and screen would be nice, but probably unnecessary.

6. Are you reusing any parts for this computer? If so say what parts (make and model).
Don't know the exact make and model, but i have a keyboard, mouse, screen and Hard drive which should be able to be re-used without too much trouble.

7. What kind of monitor/resolution do you have or want to get to use for the computer?
i'd like something half decent, but honestly i don't think it really matters. i haven't seen anything on my PC past 1024x768 in so long i don't even know what the difference would be for me.

8. Do you have already have a OS or do you need one? What OS is that?
i have Windows XP (64-bit) but i'd love Win7 for future-proofing. Of course, by the time i have the money to upgrade again we'll be at Win9 or something ridiculous.

9. What are you looking for the motherboard to have feature wise? Like SLI, Crossfire, Firewire, USB 3.0, Sata 6.0 Gb/s, and so on.
i... have no idea what any of that means. i guess i should go find a motherboard glossary or something?

10. Any plans to overclock the CPU or GPU?
If it'll get me better performance without spending extra money, F***K yes.

11. What time kind of time frame are you planning on ordering these parts?
Preferably within the next couple days/weeks, but i can wait as long as i need to if i HAVE to. After all, Planetside 2 is going to be around at least as long as its predecessor, right?