Thanks for the torrent of replies.

Anyway, never mind I sorted it out myself by creating this xorg.conf - it's probably wrong but I don't care, it works now.

Code:
Section "Monitor"
    Identifier "Monitor0"
    VendorName "Hyundai"
    ModelName "unsure"
    HorizSync 30-83
    VertRefresh 56-75
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync
EndSection

Section "Device"
    Identifier "ATI Radeon"
    Driver "ati"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device "Device0"
    Monitor "Monitor0"
    DefaultDepth 24
    SubSection "Display"
        Depth 24
        Modes "1440x900"
    EndSubSection
EndSection
I've posted it here just in case someone else is ignored and needs it