Determining a Cleaning Fee?

I clean a 4,799 sq ft. home biweekly. It is a 5 bedroom and 5 bathroom home. It also has a formal dining room, regular dining room, formal sitting room, regular living room, a huge kitchen with marble counters, sun room where they keep their dog and an office downstairs. I vacuum all throw carpets downstairs and upstairs on wood floors, sweep floors and mop, dust everything, clean windows, wipe down appliances, empty trash cans in every room, vacuum the basement, clean up their kids' toys, fold laundry sometimes and do dishes if there are any in sink. I also wash bedding, make beds, and organize and clean the sitting room off of the master bedroom. I start at 8 am every Tuesday and I don't usually get done until 12:30. What would you charge?

I have known this woman since we were kids. She is a dentist and I also clean her dental office. I actually get more to clean that than her huge home. I feel like I am being taken advantage of and not being paid my worth. Help! I am going to type up a letter to her letting her know of everything I do in her house and dental office, and asking for an increase in pay. We need to renegotiate the pay. Right now it's definitely not worth my time. Any input is greatly appreciated. Thanks!