Try to have a fx 6300. Include a dvd drive, wifi adapter, windows, and a decent monitor (1080p)
Best I could do, and it was difficult. No overclocking on this build.
you can really do more if you get a quad core
Here's what I came up with. I went over a bit. http://pcpartpicker.com/p/1QsF2
CPU: AMD FX-6300 3.5GHz 6-Core Processor. As requested by OP
MOBO: ASRock 970 EXTREME4 ATX AM3+ Motherboard. Had what I need, is a full ATX board, usb 3.0, and and a somewhat recent chipset.
RAM: Kingston Black Series 8GB (2 x 4GB) DDR3-1333 Memory. Would prefer 1600mhz+, but I couldn't fit it into the budget.
HDD: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive. Typical stuff.
GPU: Sapphire Radeon HD 7850 2GB Video Card. Cheapest 2GB version with a good cooler. I had a 1GB version and it was great.
WLAN: TP-Link TL-WN751ND 802.11b/g/n PCI Wi-Fi Adapter. As requested. I also don't like USB wifi adapters, and TP-Link is pretty good in my experience.
Case: NZXT Source 210 (Black) ATX Mid Tower Case. Cheap, NZXT.
PSU: EVGA 600B 600W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply. Budget PSU with decent components.
OD: Lite-On iHAS124-04 DVD/CD Writer. Typical stuff.
OS: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit). Cheapest, decent OS.
Monitor: LG 22EN43T-B 21.5" Monitor. Cheap monitor.