Buy thermal paste from anywhere $20 Take heat sync and cpu's out, seperate cpu and heat sync ... wipe off old paste with alchahole or meths , re-apply generous ammount of paste and put it back togeather.
be carefull to not to damage the pins!
buy 1 or 2 more fans and a 2 way adapter so you can use the same plug on motherboard.
fans can be mounted anywhere. and keep the case on.
GL!