You should try to reconfigure your X server. Sorry that I can't give you a command to do that since I use Debian based Ubuntu
Or you could manually add the new resolutions to xorg.conf and try it. As root edit /etc/X11/xorg.conf and in the Screen section, add the resolutions you want. For example:
Code:
Section "Screen"
[... I omitted this part for clarity]
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1280x1024" "1280x960" "1024x768" "800x600" "640x480"
EndSubSection
EndSection
Save the file and restart to see if you got any luck