Looking to upgrade cpu

[whatalegend123]

Im looking to upgrade my rig a little big mainly to be able to cope with crysis on minimum specs when it comes out and will think about going for a big upgrade later.
at the moment i run a
Mainboard : Intel D945GTP
Chipset : Intel i945G/GZ
Processor : Intel Pentium 4 660 @ 3600 MHz
Physical Memory : 2048 MB (2 x 1024 DDR2-SDRAM )
Video Card : Nvidia Corp GeForce 7900 GT
Hard Disk : WDC (250 GB)
DVD-Rom Drive : SONY DVD RW DW-G120A
Monitor Type : L90D+ D-SUB - 19 inches
Network Card : Intel Corporation 82801GB I/O Controller Hub LAN
Operating System : Microsoft Windows XP Professional 5.01.2600 Service Pack 2
DirectX : Version 9.0c

Im looking at upgrading my cpu a little and im wondering which will best suit my pc.Ive got a budget of up to 170gbp.I looked at a few processors and im not really sure if there is anypoint in investin in a quad core.
What cpu you think would suit me best>>??

 

[whatalegend123]

i had the impression my mobo was ok i was looking more at sort of e6300 and e6600 cpu's how much more performance will i get out of one of those compared to what u suggested? (btw i play a lot of farcry online and really want to max out visual performance and also a lot of oblivion which really eats up resources)

I fixed the sig