Nicely done :)

I suspect she appreciated the goods carrying even more than you buying it.  I offered, with lame Spanish, to go shopping for the old lady next door when I was living in Valencia a year or so ago.

Three flights of stairs not much fun, and slippery surfaces even worse.  Perhaps if you see her again you could offer to do the shopping for her while the weather is bad?

I'm glad you wrote this up and enjoy reading these gestures :)