Oh, boy. This is kind of a slippery slope. First, congrats to whoever diagnosed her with the SPD - it is so often missed. And, it is what makes this either easier or harder to deal with.
No medication will help SPD. But the correct dosage of medication can be very helpful for ADHD. What is tricky is that if you don't have a good doctor, they may be trying to medicate for an ADHD symptom which is really a SPD problem - and wind up over medicating.
My recommendation is to find an Occupational Therapist who is used to working with kids. Then treat the SPD first. There is a ton of things that you can do for SPD, but it doesn't happen overnight. After a period of time, then start a slow, cautious trial of medication if it is still needed. Probably start with a Ritalin type of med first.
The next thing to do is to find out all you can about SPD. You will have to be the one to suggest to the schools what can be done to help her. Of course learning about ADHD will also be important. There is an excellent chance that her anxiety is due to the ADHD and SPD, and some SPD symptoms are also autism symptoms.
Here is a very good link to SPD - http://www.sensory-processing-disorder.com/sensory-processing-disorder-checklist.html
And, if you have any SPD questions, we have a great forum with a leader who has successfully dealt with this with her own child at about the same age. It wouldn't hurt to read some of her own posts. But, she will also answer any specific questions you have. That site is http://www.medhelp.org/forums/Sensory-Integration-Disorder-SID/show/1396
Of course, any ADHD questions you have I will be very happy to answer.