dual monitors

I spent > one hour yesterday on the phone with a Toshiba technician trying to explain that I wanted to use dual monitors: an external monitor (HP L1925) with the S100-S1133 Portege laptop. He had no idea what I was talking about. I had successfully set up the arrangement, but with one major glitch: the external monitor was secondary. I couldn't succeed in making the laptop the secondary monitor with the external monitor (much larger) as primary. All the options were visible for the laptop, but not available. Finally, he stated it was not possible since I had ATI. The video card for the Toshiba laptop is NVIDIA GeForce Go 6200 TE 64M/6600 TE, all display drivers recently downloaded. Any help would be greatly appreciated. I am awake in Alabama, but increasingly visually impaired!