Need help on making a decent build.

[Flakey]

Can someone help me make a decent build with parts good enough to run Source engine games such as TF2 at max settings?

My budget is $500

My specs now :

Operating System
MS Windows Vista Home Premium 32-bit SP1
CPU
AMD Athlon 64 X2 4400+ 56 °C
Brisbane 65nm Technology
RAM
3.0GB Dual-Channel DDR2 @ 330MHz (5-5-5-15)
Motherboard
ECS MCP61PM-GM (Socket AM2 ) 40 °C
Graphics
E19T6W (1440x900@75Hz)
NVIDIA GeForce GT 220 (Bought HD 5770, but will install another day)
Hard Drives
313GB Western Digital WDC WD32 00AAJS-22B4A SCSI Disk Device (Fibre)
Optical Drives
Analyzing...
Audio
Realtek High Definition Audio

Can someone gather up links to parts that's good enough to run Source games on max settings? I do not need a graphics card or a case, but for everything else, I do need.

Thanks in advanced.

[Shadaez]

Everything else? Including a Monitor, and OS?

[editline]23rd May 2011[/editline]

And keyboard and all that? I'm going to assume you don't need a monitor and any of that, and include Windows 7.

[editline]23rd May 2011[/editline]

And assuming your case can take a full ATX motherboard