The GTX 560 and the GTX 1070 I linked are both rated at 150W (GTX 560 power use pulled from gpuboss.com).
You definitely could wait until the holidays to replace your PSU. It isn't a ticking time bomb. It may not be at the quality of the higher end Corsairs, but it also isn't the same as a knock-off waiting to melt in your case and burn your house down state either. I do recommend gold 80 or better, whatever you get, and a reputable brand, do some research ... if you can see it, remember to pick something aesthetically pleasing as well
You might even want to decide if you even want/need a 1070 if you are waiting that long. See how well the 1060s do and if they come out with a 1060ti this generation. Those are usually great bang for buck cards, and by later this year the dust will settle and production will catch up with demand. Realistically you'd be able to get a 1060/1060ti, a 250-500 GB SSD, and a quality PSU for less than $500 if you are on a budget. If you plan to run one card, remember your total system draw might be in the 250-350W range, so that could save you a few bucks alone by buying the appropriate PSU for your current and near future power needs.
Put it another way, two 1080 = 270x2 = 540w + 6950x 10 core 140w (actually most i7s draw same power) = 680, give 10% for overclock and you are at about 750w ... so even an overkill system really doesn't need more than about 850 watts even if it has a ton of drives and peripherals; so a 6700k @ 140 watts and 1070 at 150 watts is under 300 watts combined so even a 500 watt PSU is enough for you to run SLI if it has the power connectors for it, and if you watched the video, you'd see power from the wall at heavy cpu + gpu load doesn't really pull as much as people would like to think.