Should I upgrade to a GTX680? Please Help

I hope this is the right place to ask.

My specs:

Dual NVIDIA geforce gtx 570

daxc type: integrated ramdac

approx total memory: 4049MB

RAM: 16GB

Processor: intel core i7-3930k cpu @ 3.20ghz (12 cpus) 3.2ghz

display mode 1920 x 1080 32bit 60hz

windows 7 ultimate

my tower is a cooler master, tons of fans and a cooling system.

I ran a system requirement of Far Cry 3 and it says to get Optimal performance I need the GTX 680, but I did meet the minimum and recommended requirements of the game though.

What my question is, is it worth upgrading to a GTX 680 just for Far Cry 3 or will the differences not be much and is it even worth the current price tag? we're talking 536 euros for a graphics card!

I like to max out every single pc game that I run and play so any experts on the matter would be very much appreciated. thanks in advance.