Looking at past bargains you could get them for around $300
http://www.ozbargain.com.au/search/node/gtx+670
Cheapest on staticice I can find is $405.00 and cheapest in my state (VIC) is $455.00 not even including postage in those prices.
I currently have a Gigabyte GTX 670 OC 2GB and was hoping to get another for SLI but it's not cost effective with those price points, anyone got an idea on where I could pick one up?
That being said, is it more cost effective to sell my GTX 670 for like $270 and try find another card for around $570, what would be the best option there?
There's was a 2nd hand one on OCAU a few days ago, not sure if it's been sold already http://forums.overclockers.com.au/showthread.php?t=1109345
If you can sell it for $270, go for it. There's been new ones for less than that, and the GTX 770 can be had for about $350. I'm running a pair of second hand 7950 which I got for $400 ^_^