What can I do to help my disabled child if we live in a small town?

Talk with others. Many resources are available, if you know where to look. Pediatricians should be able to guide you to many local resources, even in small towns. I'd start with my doctor, a university developmental program, other parents, area educational agency, headstart, early access, etc. If your doctor doesn't have information. Ask to be referred to a pediatrician or a develpmental specialist.
Resources. Multi sistemic resourses envolvement.
Resources. Envolve local and government resorses and agencies in the patient care.
Resources. This is a broad question. Research the resources available to you in your town and in nearby towns. Look for both traditional and alternative practitioners. Interview them to see what they have to offer. If you have to travel to see therapists ask them to teach you how to do therapies so you can do them at home. Hopefully you will be able to find some very supportive resources.