So what's next? For a little more than the $92 they raped you for, you can get a code reader and have done that yourself!
Do you have any intentions of trying to troubleshoot this one yourself? I bought the factory service manuals from Helm, Inc. for the wife's van. Spent $100 or so, but for two phone-book-size manuals with all the info, it's well worth it!!
There are people on this site that may be able to help you out too; Flatrater comes to mind, along with one other (GMGoodwrench?) that I can't remember the user name for sure.
Or are you going to try finding a good shop?
Good luck with it, and keep us posted!