xorg - External monitor stuck at 1024x768 resolution

I'm running Kubuntu 14.04 on a older Toshiba Satellite with the following graphics hardware:

 > lspci -vnn | grep -i VGA -A 12
00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller [8086:27a2] (rev 03) (prog-if 00 [VGA controller])
        Subsystem: Toshiba America Info Systems Device [1179:ff10]
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at dc100000 (32-bit, non-prefetchable) [size=512K]
        I/O ports at 1800 [size=8]
        Memory at c0000000 (32-bit, prefetchable) [size=256M]
        Memory at dc200000 (32-bit, non-prefetchable) [size=256K]
        Expansion ROM at  [disabled]
        Capabilities: 
        Kernel driver in use: i915
00:02.1 Display controller [0380]: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller [8086:27a6] (rev 03)
        Subsystem: Toshiba America Info Systems Device [1179:ff10]

On the laptop screen, the resolution is 1280x800. I've hooked up an external widescreen monitor that I know for a fact supports high resolution (well, at least 1440x900). However, when I hook it up to this Toshiba laptop, the maximum I am allowed to set it at is 1024x768.

I have the proper Intel video driver installed and I know the monitor supports more - why can't I set a higher resolution and how do I fix it? I'm not sure if I should mess around with xorg.conf as I hear that might break stuff if I set it up incorrectly.

EDIT

> xrandr -q
Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767
LVDS1 connected (normal left inverted right x axis y axis)
   1280x800       60.0 +
   1024x768       60.0
   800x600        60.3     56.2
   640x480        59.9
VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*
   800x600        60.3     56.2
   848x480        60.0
   640x480        59.9
TV1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

The monitor is this: http://www.newegg.com/Product/Product.aspx?Item=N82E16824116066

When I try to manually generate an xorg.conf file, it appears mostly generic. Here are the "monitor" sections.

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
EndSection
Section "Monitor"
    Identifier   "Monitor1"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
EndSection