I wouldn't ask her for anything else.
I would just sell the Michael Kors (!!!) bag + wedges, then purchase myself a brand-new pair of daily sandals.
If she asks you later on how do you like the wedges + bag, just tell her you usually use them on special occasions, etc.
I highly doubt that after what her dog did to your sandals, that she would expect you to bring a designer bag into your her home!
Plus what Nanny would come to work in wedged....??!
Plus since your sandals weren't so pricey, you may have enough $$ left over for a mani/pedi.
Win win.