Suspension & Brakes - Whoa! what am I missing

I was just cleaning the car for the first time this year and noticed I am missing a bolt that must not have been put back on after my new rearend was put in last fall. I have driven the car around 1000 miles like this so Im wondering if I screwed anything up. What is the piece called I am missing so I can order it tomorrow.
First pic shows the missing side and second pic shows what should be there.
Any help appreciated.
Thanks

http://memimage.cardomain.net/member_images/2/web/626000-626999/626002_87_full.jpg
http://memimage.cardomain.net/member_images/2/web/626000-626999/626002_88_full.jpg

That's an end link to the rear anti-sway bar. No, you haven't hurt anything by not running it... in fact, you'll get better articulation in the suspension when you take it out on the trails with the swaybar unhooked. :)

No clue as to the part number you need, but I'd measure the length of the one you have, and find a matching length set in a parts store and replace both for less than you'll pay for the dealer part.

Go to Autozone, Oreilly's, or any parts store that carries Energy Suspension stuff, measure the one that is on the other side and buy new ones. I think that they are about 30 bucks. and no you did not hurt anything, but could cause the car to not handle as well.