The nouveau drivers work well with many cards but not so well with others. I hve 2 systems with nvidia cards and one works fine with nouveau but the other needs the nvidia drivers.
Have you tried the nvidia drivers, see http://forums.fedoraforum.org/showthread.php?t=280750?
Use the akmod option as that saves you problems with kernel updates.
If you are booting from the live c and haven't installed it, there is a boot option for basic drivers. These often are needed for the live cd but not for installed systems.