Editors and Statisticians for Hire
You can do a web search for "Dissertation Editing Services." You'll find links to many editors and editing companies around the country. Some provide information about cost and the type of work they do.
Although many students have had excellent relationships with independently hired editors, there are some things to know.
Some editors know APA and some don't. Be sure to ask, and don't let them fake you out if they don't know it, or you'll pay for their training. Some freelance editors and editing services offer a sliding scale depending on the needs of writers. Some can help you develop your ideas (developmental editing), though none will replace the content expertise of your faculty mentor. Some will do slash and burn editing; others prefer to go slow and easy and query writers about nearly every change. Explain your needs and negotiate an approach. Ask for references and an estimate of the cost.
Naturally, you'll want to do as much work yourself as you can, as editors usually charge an hourly rather than per page rate. You might also want to call a community college English Department or check the bulletin boards at a university.
You can also start a discussion on the topic on the writing center discussion boards at eCampus