Hi is there anyone here keen in building a budget rig for me, I'll top up additional fee for your service.
I already have the following:
Keyboard, Mouse, Speakers and 22.5inch Monitor.
So basically just need the cpu.
Computer just has to be good enough for DotA 2 in max settings.
I can offer you a list of items for your rig and you can have them assembled at SLS. If not, you can pm Fortran to build a rig for you.
CPU & Mobo: i5-3450 & Asrock B75M-DGS @ $300
Go for at least an i5 for a gaming rig if you can afford.
Ram: Kingston 1600mhz value ram 8GB @ $72
ODD: Samsung DVD RW @ $21
HDD: Hitachi Deskstar 1TB @ ~$80
GPU: Powercolor 7850 PCS @ $249
Slight overkill for dota 2. It is able to handle other games on mid-high settings on 1080p resolution. Open up your options to try new games. 
Case: Sharkoon T5 @ $63
PSU: FSP Raider 550W @ $78
OS: Windows 7 Home 64bit OEM @ $110
Total: $973
Buy and build at Tradepac.
By the way, what is your budget?