G3258 @ 4.0GHz (the standard OC achievable on most) is more than enough for CS:GO.. trust me.
I'll give a part list for $350 in a bit.
EDIT: For $350, you can't beat this -
http://ca.pcpartpicker.com/p/wk2KTW
The SSD is $80 because of my shameless plug as I'm selling it on the B&S
The package you linked earlier would be worth it at $250, but I'd be slightly hesitant buying hardware that's four years old