Definitely all three to one card, as sooth1 said. Just be sure that you're using Active MDP adapters, if you need to connect to DVI or VGA ports on any of the monitors. Passive adapters won't work.
I have three of those cards - it's easy to hook up all three monitors (or more) to the same card. Great card, too.
If you ever go above three monitors, you can connect a fourth to the card, through all the ports, but to go up to six you need a displayport hub gadget. I've not used one of those but you'll find more info on them on these forums.