you can get a PRADA on amazon.de....
L.L. Bean makes cozy ones for winter. But I'm sure you could get nice stuff at a department store sleepwear section, like Macy's or JC Penney. I don't know of any sleepwear/ lingerie stores that target older women only.
An arm & a leg! Prada shades are overpriced save your money buy something simple they'll still do same job.