Adding a PCI-E Videocard to Presario SR1650NX

I just purchased a new SR1650NX with on board ATI Radeon Xpress 200 graphics
with Windows Xp Media Ctr.Ed..

Seems like a good system.

But, my work requires a 2 monitor system, so I have to add a video card.
I'm looking for suggestions on the best route to take with this.

It seems the only options I have a

1- add a single monitor PCI or PCI-E video card and use it in conjunction
with the onboard video.
2- add a dual monitor card and disable the onboard video.

Any suggestions or experiences would be welcome. I would especially like to
know if adding a PCI-E card will give much improvemnet over the onboard
graphics.
I'm not a big game player.

Thanks in advance,
Mike Chamlee