Pushing old Hardware. (need some advice)

Hey I have some quick questions with my upgrading. (Heres the current specs)

Board: XFX MG-63MI-7159 2.0
Bus Clock: 200 megahertz
2.25 gigahertz Intel Core 2 Duo
64 kilobyte primary memory cache
2048 kilobyte secondary memory cache
64-bit ready
3072 Megabytes Usable Installed Memory ([i]Mobo only supports 4G)
NVIDIA GeForce 9800 GT [Display adapter] (GTX 460 is a couple of hours away)
Westinghouse LTV-19w6 [Monitor]
PSU (400 or 500 not entirely sure*)[/i]

Now I'm not your super hardware guy but I know the results I have gotten from this setup are far beyond what I had Imagined... Well 2 years ago, when most of the parts were just 2 years old. Now as I get on into bigger and better things My CPU and GPU are showing age, so I have decided to start the upgrade process! However the hardware on here will still be in use for maybe 4-5 months as I build a new PC so in the short term I wanted to know... (by the way I do light graphic work, quite a bit of coding and such, and am a heavy gamer, RIFT is the big one at the moment.)

What would be most benifical for me to overclock with my current PSU, my CPU or my GPU (the GTX 460 mind you.) and if I do overclock either one do I have a chance of bottle necking my PC due to power issues? (Right now I can't get the CPU to overclock further then 2.9GHZ which I have seen it higher I'm just not sure what I am doing to break it when I get it to high [PSU?])

Also, Belarc is telling me I'm 64bit ready?! Do I just need to install a 64bit OS?

And how much of a difference dose it make to ramp up my FSB, is it worth pushing to up a bit or will I not see as much of an increase as I would with just pumping up the CPU/GPU?

More info on the CPU chipset/mobo
Multiplier x FSB 6.0 x 249.3 MHz
Rated Bus speed 997.1 MHz
Stock frequency 1800 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, EM64T
L1 Data cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache 2048 KBytes, 8-way set associative, 64-byte line size
FID/VID Control yes
FID range 6.0x - 9.0x
Max VID 1.325 V

Any info will help, and don't be shy with any heavy tech speak I can for the most part understand!
~Ray

2.9 GHz from a 1.8 GHz chip is better than a 50% overclock. I do not think you have much left in the chip.

You did not mention your memory settings. If they are on Auto, you are inadvertently overclocking your memory and that may be limiting your overclock.

Core2 Overclocking Guide
http://www.tomshardware.co.uk/foru [...] king-guide

Next stop should be a guide for your particular motherboard. Google is your friend.

Go through the guides. Then take your core voltage off Auto and set your memory voltage to factory recommended values. Change the System Memory Multiplier (or whatever your BIOS calls it) from AUTO to 2.00, 2.00B, or 2.00D - whichever you need to set the Memory Frequency to twice the FSB. Then when you increase the FSB, the memory clock will rise in in proportion with it. At an FSB of 200 MHz, your memory clock should be at 400 MHz.

Download CPU-Z to check your FSB:RAM ratio. It should be a 1:1 ratio.

The maximum CPU voltage for your CHP chip is either 1.45 of 1.5 volts (you didn't say what kind of CPU chip) if you have the cooling. You want to keep the core temps under 70 C.