I'm sure the OP found his solution, but I wanted to share mine in case it helps some future seeker.
There are a lot of brand new cords on eBay for less than $10 including shipping, which is way cheaper than the $39 stereo connector kit or an AC adapter from a retailer. I just bought a used-like-new one for $5.50.
The cord is made by Volex, part number APC7Q. The Apple part number is M9573LL/A. If the seller got it from the stereo adapter kit, they'll probably list it under MD836LL/A, which is the kit's part number. I got the best search results on eBay using just the Volex part number.
Best of luck!