Question about Multi-Monitor Setup (3)

Hello (:
At the moment, I have a Nvidia GeForce 9400 GT. This graphics card has 3 ports, which are; VGA, HDMI and DVI. This has two monitors connected up through the VGA and DVI, to use as a dual monitor setup.
Whenever I try to connect 3 monitors to it, I get a message which says 'This GPU can only support up to two monitors'
The question is:
Is there a workaround this problem? Like some sort of third party software I could use?
If not.. would I need a new graphics card to have a multi monitor setup (3 monitors)?
And could I add a PCI Graphics card and connect another one using that, or would it all just conflict?

Thanks in advance!
-Dan