According to the pics on your link... you have two places for 80mm fans at the front bottom of your case. ( facing the front at the bottom)
You could put one or two fans there pulling air IN and I would turn your side fan around so it also is pulling IN air as well. Then put another fan pushing air OUT at the back under the power supply. Then that one and the power supply will exhaust the warm air.
That would be the optimal airflow for your case.