What the forget that's not how power supplies work. The wattage is the maximum output power that the PSU can supply, not what it draws from the wall. The 80 plus certification just refers to how efficiently it can convert AC power to DC power. Any power supply worth its salt silicon can and should be able to deliver it's full rated power, even though it might not be healthy in the long run.
And no, you don't need to upgrade your power supply, what you have now should be fine.