adding 4 monitors to my desktop pc

I have a HP desktop pc with Windows 7, it has a AMD quad core processor.
The graphics card on my has a VGA and a DVI output. So right now I have 2 monitors.
One is plugged into the VGA and the other to the DVI.

I want to add two more monitors to my computer. So I want to have a total of 4 monitors.

I read this article:

http://www.pcworld.com/article/251521/when_two_monitors_arent_enough.html

After reading that article.

I figured my options are to buy a new computer with an eyefinity graphics card that supports 4 monitors or buy a displaylink adapter.

I don't play games on my pc, I only want to use the internet, play video, or use Microsoft Office or other productivity software on my monitors.
Do any of you have 4 monitors on your computer?  Did you use a displaylink adapter?

Do any of you know a good way for me to have 4 monitors without having to buy a new graphics card?  The reason I don't just buy an eyefinity graphics card is because I don't think my computer supports an eyefinity graphics card, i would have to buy a new computer.

I mean using something like a displaylink adapter or a similar technology?
I think that article is like 2 years old so maybe theres a newer better solution.