Michael_400 :
As far as I know I'm not currently running a UEFI BIOS, there is a UEFI update available via Gigabyte support, but its only a "beta" and my experince is not to trust the words beta and BIOS in the same sentence.
BIOS Manufacturer: Award Modular BIOS v6.00PG
BIOS Date: 04/14/11
BIOS Version: F1
UEFI BIOS: Not Capable
My advice would be to try the beta BIOS *before* you purchase the new video card. First, read other users account to assess risk. Google is your friend, here.
http://forums.tweaktown.com/gigabyte/28441-gigabyte-latest-beta-bios.html
http://www.tonymacx86.com/threads/my-experience-with-gigabytes-beta-uefi-on-z68-and-how-to-flash-back-to-bios.70677/
Read all you can and screen for horror stories. If it doesn't sound like anyone else had major issues, I would try it out for a week. If there are no issues for you, then go ahead with the video card upgrade. If you notice any stability problems, flash the old BIOS back and delay your plans to upgrade the video card until the final version is released.
If you aren't comfortable with the beta BIOS at all, just wait for them to finish beta testing and for the final BIOS to be released. Then proceed with your upgrade