Well, for starters you need to sort it out so that all pins are pushed and securely in place. With thermal paste you want a good amount - it is quite hard to judge since too little can lead to high temps and so can too much.
I usually draw a cross on the chip and then seat the heatsink/water block allowing the pressure to spread the paste.
I would recommend you clean the chip and start again. Be really patient with the push pins too.