connecting an external monitor to my laptop

[jd]

Greetings,
On Fedora 7, Xorg -7.4-7,
My graphics chip is the Mobility Radeon 9600 M10.

I connected an external LCD monitor (1600x900)
to the laptop's vga port.

It automatically becomes a right side span of
the laptop's monitor, which is not what I want.
I would like it to have same content as my laptop's
LCD monitor.
Furthermore, I need to be able to run it at 1600x900,
and not default (as it is at present) to 1024x768.

What do I need to do to make this happen?

Thanx,

JD