What fan/cooling should i go for?

[EpicCarnage]

I've got a system with an AMD Phenom II X4 Quad Core 955 Black Edition 3.20GHz on stock, recently it's been soaring to high temperatures and crashing a few times, i've blown the dust away and now it's ok but i'd like to have the cpu cool all the time, whats the best fan i could go for. I only have around £40 to spend on one.

Thanks.

 

[EpicCarnage]

ok thanks, by apache fans do you mean these http://www.overclockers.co.uk/showproduct.php?prodid=FG-057-AK, do you just simply replace the fan on the cpu cooler with one of those?

 

[EpicCarnage]

Is the corsair H50 easy to fit? Is it worthwhile me doing that?