it is definatly possible.
if the connections on your card look similar to this
http://img.epinions.com/images/opti/...resized200.jpg
the white connector and the blue connector then your in business. if not you need a new card (and id recomend an ati card)
go to another store (the one you went to are obviously retards) and pick up a vga -> dvi adapter (
http://www.yopi.de/images/prod_pics/155/e/155743.jpg)
connect up the monitors
then
1 right click desktop
2. click properties
3. click settings
4. click monitor 2
5. then click extend my windows desktop onto this
NOTE: the software steps are for my x800 which is an ati so they may be slighly different.
this should work. its what i do