Air flow question

Hey, I have a 3.2 Prescott and my temps are as fallowing
IDLE:40 degrees
LOAD:60-70 degrees

I have a NeoPower480 that has one 120mm exhaust fan ( it exhausts into the case), then I have the fan on top of the stock heatsink, and a slow 120mm rear exhaust fan. I also added a 80mm intake fan in the bottom front.

Now, my case came with a duct already installed on the side panel for a 80mm intake fan. I could buy it and install it...BUT

The problem is, I got the PSU fan, HSF fan and (if i decide to buy it) an intake fan w/ duct blowing to the same place..(CPU).. With like only ONE slow(1500 RPM) 120mm rear exhaust fan that brings air outside of the case..I have no other spots to add an exhaust fan!

So should I install the 80mm intake w/duct, or not ( coz it could destroy air flow) ?!

**Also, WHY was the NeoPower480 designed to blow air inside of the case?? It's blowing out its hot air directly where the CPU is !

 

I don't understand why someone would design a case like that. It makes no sense.

If it helps, you should have more exhaust fans (taking air out of the case), than intake fans (which bring air into the case). Generally, air flow goes from cold at the front of the case to hot at the back, where there air is taken out.

You want to be taking hot air AWAY from the CPU, not blowing cold air onto it. If you don't take the hot air away, you don't take the heat away.

 

Ya well actually, my case is an Antec SLK2650-BQE and it came with a 350W Antec SmartPower which was blowing air outside of the case. But that was not enough voltage for my system so I bought this NeoPower480W which had really good reviews..
Now what I could do is either try to modify the side panel so I could put an exhaust fan instead or I could buy another case, but I just really don't feel like setting the whole thing up again..

And, are these temperatures critical or would I still be fine running like that?!
Thanks