Installing two graphics cards on XPS 420

Hello,

I have a Dell XPS 420 with a 425W PSU a Q9600 CPU and X38 chipset.  I have 2x 1TB HD, 1 PCI network card, and a Radeon HD3870.

My PCIe x16 slot is powering the 3870 so I have a PCIe x8 and x1 available as well as 1 standard PCI slot.

I have 3 monitors, 2x Dell 19" 1907FP and 1 Dell 22" SP2208WFP.

I currently have one 19" and the 22" plugged into the 3870 card.

Can the XPS 420 handle an additional video card of any kind to power the additional 19" monitor so I can use 3 monitors? A friend told me I can have a Radeon 7000 PCI card that he is not using but I seriously have seen a 50/50 split on the internet about people being able to use more than one video card in the XPS 420.  And the people that do seem to have success seem to have some expensive options to make this work such as swapping the PSU to power 4-port DVI cards or using DVI splitters.  I would be happy just adding a regular PCI card so I can use the extra monitor.

Does anyone have any suggestions or experiences?

Thanks in Advance.