Hi JPF,
I buy women's shoes in pretty much the same size as I do for my men's shoes. The only difference is that for a woman's shoe, it's usually necessary to get the wider versions of a given size number. For instance:
I wear a man's size 13, usually with normal or normal-plus width. I also wear a woman's size 13, but with a wider width. The only way to know for sure is to try them on at a shoe store, and you'll probably have to go to one that specializes in larger woman's sizes. Most regular shoe stores go up to a 10 or so in woman's sizes.
Is there a community of Black folks near you? If so, shoe stores there may well have your size since Black women tend to have larger feet than White women. I go to such a store in Oakland (California - USA), and they're very friendly and helpful. Here's a picture of a nice pair of pumps that I got from them.
John