To answer your original question, I would try to solve your current cooling problem rather than investing in technology that will soon be outdated. To address the cooling problem there are some things you can try. First, as @dangus suggests, you can try reapplying the thermal paste between your cooler and the GPU (by the way, what brand and model of 7850 do you have?) If your case allows, you can also add some fans to it. You could also also try a PCI slot cooler like this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835888112 (not recommending this necessarily, just an example.)
EDIT: Actually this isn't the best example, it's a PCI (not PCIe) slot cooler. But you get the idea.
When buying fans, the higher the "CFM" rating is the more it will cool - but it will also be louder.
Also a lot of cooling problems can be solved by just blowing the dust out of your case and fans.