siren

My pc is seriously overheating! I'm running a GeForce6600, a P4 3GHz 2MB, an ASUS P5N32-SLI DELUXE Mobo, and I'm using Antec's Sonata 2 as a case...I'm looking at fans on newegg, but I need to know what power connector to use... does anyone know if I use a 3 or 4 pin connector?

Also, the sonnata 2 has an air duct in it that leads from the back to the VGA and the CPU....the CPU has an out of box fan and heat sync on it, but I was wondering if it would be smart to put a fan above the fan to the cpu....the air duct has a spot for a fan to sit above it, but I didn't know if it would be alright....

any help would be awesome,
thx
siren