Upgrading My PC. Suggestions Or Advice?

[IRhythMz]

My Computer Specs:
430W E-view PSU.
E-View ATX Case Happy 16H
Intel C2D E4500 2.2GHz @ 2.6GHz *Overclock*
P5GC-MX MoBo.
3GB 667MHz KINGSTON RAM.
Gigabyte Nvidia Geforce 210 [Core: 625MHz Shader: 1452MHz Memory: 835MHz] *Overclock*
160GB Hitachi HDD.
Windows XP SP3.
DirectX 9.0c

I Decided to buy 2 New CPU Case Fan Because worrying i'll toast my PC.
500GB Samsung HDD. And, Maybe Upgrading a total of 4GB in my PC.
The issues or problems is...
The Proper airflow in my Casing,i only can use 1 case fan connect to a 3 pin CHA_Fan on my MoBo, and the other 1 Case fan im gonna do it on 4 pin molex Connector(Btw,Still confuse about the molex,i watch youtube ppl short wire it,i not dare to do such things,decided buying an adapter for easy install using Sata which is 4 pin thru the PSU)i know Windows XP Cant use a total of 4GB Rite? Are thr any other way? like went into the bios or download a 64bit mod for xp?
Help Help Help. Still newbie in this stuff. Image of my PC and more stuff involve:
http://www.facebook.com/photo.php?fbid=288520081172282&set=a.203332513024373.51325.100000428769758&type=3&theater

 

[o1die]

Avoid windows xp 64; I tried it once and had too many virus attacks. Look for windows 7 64 on craigslist; I've seen it unopened as low as $50. You have a low end power supply. I would stop overclocking your video card; the difference in performance is too small to risk a component failing if you're poor and can't afford to replace it. You need a better power supply to overclock. I noticed a bigger performance with a modest overclock of the cpu (20 %). Your board may or may not permit it.