Do I need to use the same video card to support multiple monitors with Windows XP?

It depends what kind of multi-display do you want. If you want same picture (clone) on more than monitors, you can use a "VGA Splitter". If you want to have extended desktop, (open two different windows on two monitors) then you need to have a video card that supports 'Dual Display', that would be about $70.

if you had a Dual monitor card on the pc to use 2 montiors at the same time then use it again or you can try this it is verry good more then Dual setup its a multi set up http://cableorganizer.com/kvm-switches/8-port-rackmount-kvm-switch.htm

for older models you need a seperate video card for each moniter. the video cards must also be cards that are specific for a certain model of moniter. there are newer video cards that support duel moniters. it must be specefic to the moniter though

u can and just buy the split cable for the monitors.this would create less work for u and the pc.