My home system is running pretty hot these days. The northbridge is holding a steady 60C

with Motherboard at 34C.
My current heat sink, Zalman Volcano I think, doesn't seem to be working too well.

I see that number6 recommended a Thermalright? Do you all like this one?
my system specs:
Asus A7N8X deluxe
AMD 3000+
ATI 9500 Pro
Antec Case (single fan at rear)
My room temp is at about 80F. But I think the air flow to the back of the case is poor (Located in corner under a shelf)
I though of putting a small 6" fan behind the PC to clear the air that is settling in the corner. I also thought of getting one of those cold cases, but not sure of what brand and assumed the cost was relatively high.
I am no expert in hardware and need some guidance.
Thanks.