Question : Where can I find the video bios update for this video card?

The ASUS EN9600GSO

This one: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121251

The current version of the video bios is 62.92.3B.00.00

Answer : Where can I find the video bios update for this video card?

This is the Asus page for your video card. Under downloads it does list a new BIOS version, but not for your exact model of card...it would appear there are no BIOS files available for it.

http://www.asus.com/product.aspx?P_ID=PE5WniZxEGltnkI1&templete=2