Fans

Hi! Happy new year to everyone. I hope you guys can shed a light in this problem of mine, i have this case with a 3 built in fans, a 120mm fan at the back of the case, a 140mm fan at the front of the case and an 80mm fan at the side panel. I bought a xigmateks thor hammer with dual-fans and mounted it on an am2+ gigabyte mobo and i notice that the 80mm fan on the side panel is on the way, so i took it out. When it was mounted i have face with another problem, i cant turn the thor hammer to blow fans to the rear. The fans could either blow air to my gpu under the case or to my psu above the case. Someone here in the forums told me to blow it down to the gpu. is that good? and my 140mm fan at the front of the case blows air into the case, and so is the 120mm fan at the rear, is that good too? or should i make the rear fan exhaust air? thanks for all that would reply. and im sorry if this was so long. and im sorry for my english too. thank you all and happy new year.