Hi,
I will try to answer. First, did you look on
http://www.linux-on-laptops.com/ ? It's a good src of help.
So, using gnome menu, you can choose manually your lcd configuration in: System settings -> Display -> Hardware. After, you choose a generic lcd similar as yours.
Else, you can edit your /etc/X11/xorg.conf file.
I have a sony laptop with a 1400x1050 lcd. These are "monitor" and "screen" section of my xorg.conf:
Section "Monitor"
Identifier "Monitor0"
VendorName "Monitor Vendor"
ModelName "LCD Panel 1400x1050"
HorizSync 31.5 - 90.0
VertRefresh 59.0 - 75.0
Option "dpms"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 16
Modes "1400x1050"
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1400x1050"
EndSubSection
EndSection
I hope that my xorg.cong will be a constructive help.
Good luck!