Cooling problem

Guys i've tried to keep my pc as cool as poss with fans without buying the water cooling. Due to my actual tower being a mid size one. But the fans i've got are exhaust fan underneath the graphics card, 1 cpu fan, 1 fan at the back of the pc. I was thinking of putting in another fan to blow in more cool air, i've done a picture of my pc [hopelly understand where i'm coming from]

Would it be ok for that? wont blow any hot air in would it.

http://i21.photobucket.com/albums/b2...ughter/Fan.jpg