Florida Hospital Misleading quotes Orlando, Florida

My wife had surgery to remove a tumor in September 2009. Prior to the surgery we requested quotes from all parties involved, we received a quote of $17,500 from Florida Hospital and Florida Hospital offered a 50% discount if we self pay. We do have health insurance, but the 50% discount meant less paid out of our pockets than if we used our insurance. After careful consideration we decided to go ahead and self pay the hospital. We had to pay the hospital the day before the surgery, on this day they quoted us $21,500 for the same procedure and we paid $10,750. The surgery was a 2 hour outpatient procedure and was a success, everything went well and there were no complications. A week later we received a bill for $47,000 for the surgery and the hospital notified us that we had to pay an additional $12,700, being the 50% additional fee. We queried this amount with the hospital and they said that there had been an innocent mistake with the quote and they had forgotten to add a $25,000 equipment fee to the quote. We are not able to pay this additional fee, the surgery has cost us $18,000 to date if we add up all the doctor's bills, MRI and scans, blood work and tests. We have drained our savings and we are at the point where we either need to sell something or take out a loan to pay the hospital. If we had been quoted the correct amount of $47,000 by the hospital then we would not have proceeded with the laproscopic surgery and we would have gone with traditional surgery which is cheaper. We have discussed this with the hospital and they requested our financial information, after reviewing our financial status they said we can afford their mistake. They did offer a reduced fee if we pay by a certain date, but we simply do not have the cash available.
We feel mislead and taken advantage of and at this point we are very stressed about this situation and my wife is very depressed because she feels it is her fault.