Hi M. -
As usual, the Moms here have great advice -- Joanna knows about PHP because she works there (hi Joanna!) and it is the very best resource to start with here in the Bay Area.
Misdiagnosis is fairly common, but usually the 'other way around' -- meaning, that kids are frequently diagnosed with ODD or AD/HD and then later get a correct diagnosis of AS.
I work with neurodiverse kids (those with AS, AD/HD, bi-polar, learning differences) ages 14+, and have a 15-year-old with Asperger's, so know how scary this can be -- however, with early (and GOOD) intervention, most of our kids go on to have wonderful lives.
Hook up with PHP, and (not to toot my own horn) check out The Mom's Guide to Asperger's Syndrome -- it was published last year, and is FILLED with information on how to work with elementary school Aspies, how to advocate for them, where to find help, etc. I'm working on the second one now for high school students, and hope to have it to press in a couple of months.
Feel free to contact me if you need more info -- you're a great Godmother for helping out!
J. J-T
EvoLibri Consulting