Alternately you can go to the Asus site and all the files and info you need are there. (enter your exact motherboard info into the lines as requested and Win7 64bit when the little window pops up. It wouldn't allow me to give you a direct link)
Look under "BIOS" and "BIOS Utility" for downloads and look up in the left corner of the page at the links and there's instructions as well.http://support.asus.com/download/download.aspx
NOTE: Make sure you know what you are doing or you could end up with a paper weight. Flashing should only be done if you have an issue you are attempting to cure or you know there's a fix in the update that applies to you.
Otherwise a good rule of thumb is if it ain't broke don't fix it.