Should I add a couple more fans to my case?

I am wondering now if I shouldn't get an extra fan or two to provide more airflow inside my case? If you look at the photos below you'll see my tower is down in this little cubby hole and it barely slides in there. But I still think I can get some fans on that side panel.







Now my problem is I don't know squat about airflow inside a case. Should I put fans blowing out or in on the side panel? And what type of fans would be best? Right now I have some foam over those side panel holes to keep the dust out. The case only has three fans (120mm) - one on the Thermalright 120 UE, one in the front ,and one in the back (not including the PSU fan).

Thanks for your input.

Hi tecmo. I had started a thread here to ask about a new graphics card, because I'm starting to see artifacts on my monitor now and then. In that thread I asked this question, but I thought maybe I should start another thread for it. I'm going to be buying a new card and some RAM and I wondered if I shouldn't also buy some extra fans while I was at it.

The reason I'm thinking about fans is because when I started asking around about the artifacts many people believed I was having overheating issues with my card. I know I'm not because I've checked inside the case and the heatsink on the card is cool to the touch. So I thought just to be safe than sorry maybe I should add a couple more fans to the case. As you can see by the pics I have two open grills on the side door where I could put one or two fans. The round grill is right over my huge Thermalright Ultra 120E so I couldn't put a fan inside - it would have to mount outside somehow, but then the Ultra already has a big 120mm mounted right on it.

I could put a fan on that bottom grill, because that lines up with where my video card goes. I don't know much about fans so any info would be appreciate - advice on the fans, placement, mounting, etc.

Thanks.