Nope. You won't even be able to run both cards on the recent drivers, the 560 is a Fermi I believe, without driver support. Just stay with the 960.
I would advise against that if it's for gaming. Very few games support SLI properly these days, some don't support it at all, it seems to be kinda dying. If you want it for games, check if the games you wanna play work OK with SLI so not to waste money for nothing. Unsure if you need SLI for tasks like rendering etc., probably not, but you'll have to check again. Just slapping in 2 GPUs could work, even without the SLI bridge.