Has the school done their own evaluation? Have they seen diagnostic reports and acknowledged that the needs are real? I am less familiar with the 504 process, but for an IEP the evaluation step is key-- once everyone agrees on the needs, accommodations are decided on based on the needs.
We always bring our outside experts to these school meetings to advocate for us; if I as the mom explain the issue, I may get no buy-in, but when someone with a degree and professional standing does the explaining, the school folks are much more responsive. Do you have someone like that (who diagnosed the dysgraphia and anxiety, for example?) whom you could bring in?
Is there anything here (in the bibliography) that's useful to you? http://www.wrightslaw.com/info/read.dysgraphia.facts.htm
or here ?http://www.wrightslaw.com/info/test.written.lang.htm