The s1070 isn’t a huge watt sucker, figure 300 watts worst case, 175W typical for CUDA apps. So the rest of your system’s wattage is important.
But with a UPS, be very conservative and don’t even come close to overloadint it. I have a thread here on the forums where I talked about my multi-GPU system failing (and UPS smoking) because of its constant load on the UPS, even though that load was well within the UPS’s stated limits. So if your machine is using say 500 watts, and it’s running 24 hours a day, I’d be as conservative as saying you need a UPS that’s listed as being able to provide 1000W.
The actual wall-socket power draw is critical for your decision here. Get a $20 Kill-o-watt and measure it directly when you’re machine is under top load. It’s very easy to mis-estimate your machine’s power use (usually you overestimate.)