You may not have to choose based on the cost of private special ed services. Under IDEA 2004, LEAs (Local Education Agencies) are responsible for providing "equitable services" to private school students within their boundaries. It is possible that some services for your child could be included in this if she enrolls in the private school

http://www.wrightslaw.com/idea/osep/faqs.parent.placemts.pdf

To be clear, there is no IEP requirement, and no individually mandated services to private school students like there are for public students, but the district does have to provide some services to private school students with disabilities, and it is worth checking out to see if your child's needs could be included there, if you feel that the academic environment at the private would be a better fit.

If the anxiety is severe enough that you and your child's therapist feel that a regular PS classroom would be inappropriate, you can always disagree with the school's proposed IEP and ask for tuition and special ed and related services reimbursement for the private school and the Orton-Gillingham tutor, if that is what is clearly needed. They will almost certainly say no, but you can either enroll her in the private school anyway and press ahead with the appeals process at that point, (considering the fact that they completely failed to provide an appropriate education in the year that she was enrolled, and their teachers' behavior toward a child with a previously documented physical disability is largely responsible for her current anxiety) or use the threat of doing so as leverage to get the tutor provided at public expense or to get a better IEP at the public school.

BTW, the local public district is responsible for evaluating private school children suspected of having disabilities under the child find provisions of IDEA, so if they told you that they were not, that is a red flag regarding how well they may be meeting their other obligations under that law.

It is also worth noting that, when the time comes to develop the IEP if you choose to go with the public option, you might want to push for accelerated work in her areas of strength in order to help reduce her anxiety, with supporting documentation from her therapist. If the advanced work is required to help ameliorate one of her disabilities, then failure to provide it is failure to provide a FAPE.

I really recommend familiarizing yourself with the material over at wrightslaw.com before you get too much further into this process.