Looks like
this adapter is what you need, based on the specs on
this page. That page indicates a mini-DP port on the system.
Here's an alternate source, I suggest using the Google Checkout option if it's an option for you, they had a security breach 2 years ago but I haven't heard anything about them being a risk recently. Other than the security breach 2 years ago I entirely trust the site, the prices are MUCH better than most other places and the cables work the same. I have 3 of their HDMI cables in service right now, they've been in use for 5 years. Shipping my be a little high in some cases but depending on how much you order the overall cost should still be lower. On this particular item, shipping is a VERY reasonable $3.00 to my door.