You should be able to update the bios through the software asus provided with the mobo. Don't ask me how (im sure its self-explanatory), since i don't use that software. I update it through the bios itself. Get a jump drive with the file (not the zip but the actual bios file) on it and plug it into one of your active usb ports. Then restart your computer and hit delete a couple of times after the mobo screen disappears or it finishes checking diagnostics (which ever you have it set to), and go to the tools tab and pick the EZ Flash2. Find the jump drive with the bios file with the new screen and hit enter and it should ask you are you sure and all that other stuff. Then it should update. Everything in the bios will reset and don't try saving your current profile and trying to activate it with the new bios (i found that out the hard way).
If i didn't explain it well enough, you can download the manual here
. Just select the correct stuff in the tabs to get to your mobo. You can dl everything you need for your mobo here...including the manual in pdf format. Dl the manual and go to page 67 (just enter the page number at the bottom of adobe reader). It will explain how to update the bios like i said previously along with other methods.
That should answer your question. Have fun