Circulation???

What is the ideal air circulation system for a 4x4x7 room with a 1000w. HPS and where can these fans and supplies be purchased online? I wanna make sure I have the right amount of circulation and with no light leaks. Thanks for all of your help in advance.

What I am trying to say is that I would like to have one exhaust fan and one intake fan (obviously I would have an osilating fan inside moving the air around) but that they would have enough power to keep the temps to their optimal if I leave them the duration of the lights being on. What fans would you suggest so I could achieve this system?