Buying a GTX680, will the rest of my system be a bottleneck?

Hi,

I am considering the purchase of a "Gigabyte GTX680 SOC 2gb" video card (Link) but I am starting to wonder whether the rest of my system's components should be upgraded first. I am thinking that they may be too much of a performance bottleneck to warrant the purchase of the new card.

I currently have:

• i5 760 - overclocked to 3.4 ghz
• 8gb DDR3 1333 MHz RAM, probably will buy some 2133 MHz when I get the card
• 750W TP-750 Antec PSU
• GA-P55-USB3 motherboard, with two x16 GPU slots (one operates at x4 when in crossfire/sli though)
• HAF-X case

I am sort of asking two things.

Firstly, will my PSU even provide enough current to run the card? The card requires "a minimum 12V current rating of 38A" yet I cannot find the current that my PSU can supply. It does however have "4 +12V output circuits", whatever that means. Where can I find the maximum current that it supplies?

Secondly, assuming my PSU is up to the task, will the rest of my system be too much of a bottleneck to even benefit from a faster graphics card? I currently have an HD6870 and will buying a faster card be that much noticeable with the system that I currently have? Or should I spend the money on upgrading the rest of the system first?

EDIT: Link
This person has a similar setup - same PSU and essentially same CPU - and his seems to work fine. Maybe the PSU is ok!

Thanks for any help,
James