My family and I were in this exact same situation last year, with the same company -- Green and McQueen. They wanted $450 for ours so we never did get them.
Here's another link that may be of interest. Several people filed a complain with the Govt.
A co-worker recently went through the same situation, again, dealing with the same storage company.
My best advice is to ask your family doctor for copies whenever something significant occurs with your health. They may charge you a "reasonable fee", but at least you won't be charged a fortune to get copies from storage.
Keep in mind that I do NOT blame Green and McQueen for this. They are simply a company that provides storage services for medical records. (Although their fees are rather suspect) It's the Doctor and/or the medical board's fault. There should be something in place that provides patients with sufficient advance notice that the practice is closing so that they can obtain copies from the doctor for a true 'reasonable fee'. If the patient chooses not to ask for copies at that time, then fine -- charge them more for copies from storage.