Canon 5D Upgrade

I have had my Canon 5D (1) for 5 years and am thinkiing of upgrading/changing camera bodies. I am interested in the comparative image quality between the 5D , 7D and the latest 6D. The 5D Mk111 is unfortunately out of my price range, but maybe i  could stretch to the 5D Mark 11....Just don't know which way to go. Main interests are landscape, nature, and sports in that order. I currently own 17-40L, 24-105L and 70-300 USM Zoom lens.

Any suggestions / comments would be welcome