If the pci card needs to be "seen" first, maybe you should make the pci card, card0, and the agp, card1...
For the more obvious,
in each Section "Monitor" you need values for hsync and refresh, as per your monitor specs,
in Section "Screen" you need "modes" for each depth and a "DefaultColorDepth" for any "screen" with more then 1 depth listed.
Refer to acid_kewpie's file, you got it all in there.
