I am 90% sure that it is compatible. Looking at a top-view pic of your motherboard,
here
It looks like it has the same mounting pins for the NB sink that my motherboard does, shown
here
The compatability lists for the HR-05IFX show 780G and 790FX chipsets from Gigabyte, and I'm pretty sure that all of AMD's 700-series chipsets use the same mounting methods.
It looks like it will fit just fine. If you don't have any AS5 I would order some along with that HS, you'll need it. The TC that comes with it isn't the greatest.
Getting an 80mm fan (the fan clips on that HS only work with 15mm thick fans) might be a good option too, just to go ahead with some cooling overkill. Newegg sells 80x15 fans for relatively cheap, but I don't know about that site you found it at. That price looks good too, I think I paid 32.99 for mine on Amazon.
||ASUS G51GX-RX05 - Intel Centrino2 P7350 2GHz - 4GB DDR2 800MHz - 1GB nVidia GTX260M - 2x320GB Raid0 (coming soon) - 42" Insignia 1080P LCD ||