You are good with that setup but I'll recommend you get another 4GB stick of ram(same frequency and latency)
You should change your motherboard to a better board like ASRock Z77 Extreme 4
You need to have a power supply of 700watts run this setup but you can get a 800watts one just to be futureproof.
Two HD 7970 GHz Edition cards in crossfire is better than two 680 at SLI http://www.anandtech.com/bench/Product/585?vs=588
(the link here uses a normal hd 7970 not a GHz Edition card which is faster)
Your processor is ok but consider to upgrade whenever you can.
Honestly I think two 680 cards is too much for your specs with one 1080p monitor.