What about calling a place like ARC to see if they can point you in the right direction?
http://www.arc-resources.org/Home.html
They provide advocacy and assistance for people with developmental disabilities. This includes individuals with disabilities that result in expressive and receptive delays and learning delays. Even if they can't help in your particular situation, they may be able to provide you resources in your area that could.
I know how frustrating the diagnostic process can be. My dd was not dx until she was 7!!! Her ped. kept telling us he knew "something" wasn't right, but couldn't pinpoint it. He sent a myriad of referrals which were denied by insurance. We did make it in to see a Neurologist at Stanford that told me I was "micro-analyzing" her and she was fine. (She is now 12 and has multiple delays...working at a first grade level, etc....so much for being "fine"). She was evaluated by our local school district at 3 and qualified for special ed., but they were still unable to provide us with a dx. They approached her issues solely from an academic stand point and said she was "educationally retarded". As it turns out, she was dx with PDD-NOS with significant delays in expressive language, an array of sensory issues, etc. The road to get there was frustrating and looooonnngg, but I am glad we didn't give up. Keep on pushing, calling everyone, submitting referrals, etc. It will be worth it in the end. Though a dx won't change your child, it definitely helps you to understand your child and find appropriate resources specific to your childs needs. Best of luck to you!!!!