The GTX 760 draws ~170w on the 12v rail, and your CPU is a 65w TDP model. The rest of your system may draw up to 50w, though probably not all of it on the 12v rail. That's a total of 20-24a on 12v, and ideally your power supply would have 25-33% extra capacity, so 30-32 amps 12v.
Be aware that brand is actually more important than watts. A cheap unit can claim a huge watt capacity but will give "dirty" power that can harm components, and it will likely die sooner too, possibly taking your other parts with it. I fix computers for a living and just today I replaced a power supply causing instability.