ATI 5770 in XPS 7100 with 3 VGA monitors

I have an XPS 7100 with ATI 5770 garphics card runniung Win 7 Home Premium. Currently drive 2 * 22 inch LG VGA monitors at 1920 by 1080 from the DVI ports on the video card. I have just aquired a 3rd LG monitor and want to add this to the setup.

I beleive that I can do this with a Display Port - VGA adapter. One on Amazom for 20 pounds. http://www.amazon.co.uk/StarTech-DisplayPort-Video-Adapter-Converter/dp/B003V4TV8O/ref=sr_1_2?ie=UTF8&qid=1327913748&sr=8-2 

Is this the best plan - should it work?

Thanks