Corsair gs600watt psu

Yes - good PSU.

just to let you know, it's not enough power to power up 2 Radeon 7970 or 2 GTx 680 lol but surely be able to power 3 GTx 560Ti

plenty of power for any single GPU card

 
I wouldn't reccomend it for either but,
If you think it could power 3 x 560Ti's what would make you think it couldn't power a pair of 680's ?

http://guru3d.com/article/geforce-gtx-680-sli-review/4

http://www.guru3d.com/article/geforce-gtx-560-ti-sli-re...

~90% efficient psu used in reviews
473w AC = ~426w DC = ~ 71% load on a 600 watt psu
449w AC = ~405w DC = ~ 67%

Based on running nothing more strenuous than a game like load for a few hours a day, and not having a fear of surpassing the magical "50% load for optimal efficiency and extended psu life" number during those few hours , either of the configurations in the reviews could run on it ( with the use of adapters )

A third 560 Ti ? No

so my plan is like gtx 560ti ... or the same price card of kepler series or in ati 7series will it be enough i have i52500k with h67 mobo

Yes, it will be enough for your rig with a single card of any of the GPUs you listed.

Corsair is a quality brand so it should be alright. It can even power an GTX 680 if you want to  

really ? it can power gtx 680 ?

Any serious brand 500W 80+ PSU can power a single high end card.

It has the proper connectors and has 48A on the 12V rails; more than enough to power a single GTX 680.

personally I would like a little more headroom but it can even power AMD 6990 & Nvidia GTX590. for cards like the GTX560ti, it's perfect.