This looks like what you have:
If this is the right one, then it has Intel GMA 900 graphics
Some snooping around suggests that the driver for this will already be in your distro. Look in /usr/lib/xorg/modules/drivers for something like this:
In the device section of /etc/X11/xorg.conf you would simply specify "intel" for the driver.
Once the right driver is setup, then you should be able to enter the desired modes in xorg.conf