You can use the link provided to download the correct files. To update BIOS:
1. Extract the BIOS file if it is in a ZIP file.
2. Copy the contents to the root directory of a USB flash drive. What this means is that the BIOS files should not be inside a folder, just directly in the USB drive. So when you open the USB drive, the files should be there, and should not be inside a folder instead.
3. Shut down the computer on which you have to update BIOS, and then plug in the USB drive.
4. Start it again, and enter the BIOS.
5. In the 'Tool' screen on your BIOS, click on Asus EZ Flash 3 Utility. It should ask you how you want to update the BIOS. Click on USB.
6. If it asks for confirmation, go ahead and do it, but first make sure that the PC is receiving interruption-free power - cutting power during BIOS updates will be fatal for your motherboard almost always.
7. LEAVE IT ALONE. Don't touch anything until it says the update is complete - don't press anything, don't move the mouse, hell, don't even look at the screen too much. Let it do its thing, because it's doing something very sensitive.
8. BIOS should be updated now.
Edit: your BIOS settings will be reset when you do this.