No need to read much into that wattage calculator here.These calculators overestimate system power consumption.
This config is not going to consume 250Watts even at full load.
Check this:AMD Radeon HD 7750 and 7770 review - Hardware setup | Power consumption
The power consumption there was calculated with an overclocked i7 965@3.75GHz which consumes more power than an i5 3470.
Also this: Power Consumption : AMD Radeon HD 7770 And 7750 Review: Familiar Speed, Less Power
Here an i7 3960x@4.2GHz was used which consumes significantly more power than an i5 3470.
No need to worry for power consumption here,that PSU is fine enough to handle those with ease.