We all know how sweet you are and that your heart was in the right place, Tricia. Hormones are very powerful things!
I was in a similar situation once and I wanted to help but didn't know what to do. I just paid the person's (elderly) bill when I paid my own and left without telling her. I hope she wasn't embarrassed or upset, but by then I was long gone and she didn't know who I was.
She had been kind to me, so I just looked at it like repaying her kindness.