Oxygen gas at 34.5 degrees C is compressed from 45.7L to 34.5L against a constant pressure of 0.987 atm. If the oxygen gas is defined as the system,

Oxygen gas at 34.5 degrees C is compressed from 45.7L to 34.5L against a constant pressure of 0.987 atm. If the oxygen gas is defined as the system, how much work is done (in J) on the system? (1L atm = 101.3 J) 

I know that work = -pressure times change in volume but I like by only using that equation I would be skipping a step. I'm guessing that I need to incorporate the temperature into the equation somewhere but I'm not sure how.