i5-2500 = 95W (and it will hit this with the demand a GTX1070 will put on it)
GTX 10570 = 150W
If you add in the fans, drives, etc you are looking at around 350W. That doesn't leave much left over, and I assume this power supply is somewhat older? They do age over time and become less capable due to capacitor fatigue.
I recommend either a lighter GPU, (i5-2500 is going to be limit your FPS), or upgrading to a 550W power supply to have some safety margin.
Also you need to consider things like plugging your phone into the computer to charge, or having wireless mice with charging stations.
The PSU should be replaced if you decide on anything other than a 1060 or lower. RX cards traditionally use more power than GTX. If you have some time to wait you may see what the '2060' will require and what kind of boost in perf to expect.
If it's a right now, why chance it for ~$50?
I think there's enough headroom here.
However, I will go for GTX 1060 6GB.
Can you answer my second question please?
I'm gonna play games on Samsung 49" 4K Smart TV.
Should I just go for XBOX ONE / PS4 or play with my current PC with 1070 / 1060 ?
Is it fine to play PC games at 1080p on 4K TV?
you will spend less on the 1060 than the x box, and in regards to resolution, yes the 4k tv should do fine at 1080. It likely caps at 60hz. Without looking at literature on it, the easiest way to find out is hook up a PC and look under advanced graphics options to show supported modes.