I get calls from potential customers who say they have my card or leaflet or seen me in a magazine, when I ask where they live, they are normally in areas I canvassed years ago, the record so far is 4 years, yet they have just seen me.
If I was you I would re-quote to reflect your price increase and if she agrees carry on cleaning.
How many times have you seen and heard from cleaners on this site using crap but cheap equipment, but end up paying for something that lasts and works better.
You will find that because she has come to you, you are in command and if she does become a customer from hell, well then you can dump, but what if she is won over by what you do, imagine the testimonials she can give you and your company.
I walked into a rolls royce dealership years ago and couldn't afford one, if I ever get the money to buy one, do you think they will refuse to sell me one, if I went back?