You should try to see whether the Xorg nv driver works, grab a modeline with xvidtune and store it in the Monitor section of your xorg.conf.
Finally, I have discovered a little trick that I described here
to make the drivers work somehow.
Hardware: Dell Inspiron 2650, P4M @ 1.8 GHz, chipset i845, 512 MB RAM, nVidia Geforce 2 Go with 16 MB RAM, 20 GB HDD.
Software: BIOS A10 (3.11.01.52.AB video BIOS), Fedora Core 4, Kernel 2.6.12-1.1398_FC4, Xorg 6.8.2, NVIDIA 7667 drivers.