1060 isn't expected till the Fall I think so if you return it you might have a little wait. Do you have a card to use in the meantime?
You will likely have to wait a few weeks for the 1070 too but obviously that is coming much sooner.
Relatively speaking I think the 960 is/was an underpowered card compared to other generations of x60 so get an upgrade if you can. The 1070 is likely to blow 1080p gaming out the water, good if you have 144Hz monitor, a little wasteful if it is only 60Hz.
There are probably loads of cheap 970s hitting ebay etc. around this time or going new with special deals so that might be working looking into, if you can get it for the right price, as it is a great 1080p monitor card and a very decent step above the 960.