I wouldn't trust the school psych as the sole evaluator if you suspect a disability. (Their training is limited, and they have a conflict of interest; they may be pressured to find no disability so that the district is not on the hook for services.)
See if your insurance will cover the private evaluation, and talk to the private psych's office about funding opportunities. You can also contact your county/city to see if they have financial assistance in evaluating for developmental disabilities. Here the county will often pay for the eval if your insurance won't.
DeeDee
