The file you downloaded from Softpedia appears to be a BIOS firmware upgrade. This is not something you should install without great care, because flashing the BIOS with incorrect firmware could render your computer unbootable. (In essence creating a very large paper weight.)
In general I don't recommend downloading drivers from some random place. You should if at all possible download them directly from the motherboard manufacturer, in this case Gigabyte.
I suggest you go to their driver download page and get the correct network device drivers.
http://www.gigabyte.com.tw/Support/Motherboard/Driver_List.aspx