Buy L4d Serial PC Upgrade Or Buy An Xbox 360/ps3?

PC upgrade or buy an xbox 360/ps3? - buy l4d serial

I am planning to upgrade my PC updated
buget $ 300

Specifications:
Pentium Dual-Core E2140 (1.6 1M 800FSB)
Intel ® 945G Express Chipset Intel ® ICH7
Cache 1 MB Transfer Cache
Memory 512 MB DDR2
Expandability Expandable to available up to 2.0 GB (2 slots, 1)
Memory Speed 533/667
Supports High Definition Audio Integrated 5.1-channel audio
80.0 GB HDD 7200 rpm SATA
Lintel optical drive Graphics Media Accelerator 950
Video memory up to 128 shared video memory
Communication K56 Flex ITU V.92 modem, data / fax
Network Integrated 10/100 BaseT network interface (Broadband Ready)
Media Drive 9 in 1 card reader
Windows Vista HomeBasic
I / O port USB 2.0, 2 PS / 2, 1 parallel, 1 serial port, Line in, Line-out, Mic-in, RJ-11, RJ-45
Display 15 "Acer LCD Monitor
USB keyboard
USB Optical Mouse MouseVD-RW Dual Drive
Video Graphics
Total Expansion Slots 1 PCI-E x16, 2 PCI

Acer M1640 model
I would like, what kind of graphics card and processor I recommend you to play some newer games like World of Warcraft and L4D (or prototype, if possible, to know) without problems.
THX