I have a similar card. Here is what I did:
OK, in GRUB, you need to press a key to stop the timeout. Then use the commands (I can't remember, but they're listed at the bottom of your screen) to edit the kernel arguments. When it allows you to edit them, add the number 3 to the end of the line. This lets you enter runlevel 3, the text mode.
From here, add to /etc/yum.conf:
[livna] name=Livna.org Fedora Compatible Packages baseurl=http://rpm.livna.org/fedora/$releasever/$basearch/RPMS.lvn gpgcheck=1 enabled=1
If you've never used ed, I'll help you out. Use these commands:
/. (repeat this command until met with a ? mark)
[livna] name=Livna.org Fedora Compatible Packages
next a command prompt should reappear:
rpm --import http://rpm.livna.org/RPM-LIVNA-GPG-KEY
yum install ati-fglrx kernel-module-fglrx
Then edit your driver in /etc/X11/xorg.conf:
/. (repeat until you find the line with the driver, probably "VESA Generic")
At the next prompt, reboot normally, and your video should work properly!