This may be a non-answer answer...
but a woman's size 5 is the same as the largest girl's sizing (meaning the size which ends children's sizing). I think is a 4 (maybe wrong with that number).
I just remember being told when my daughter was wearing the last children's size...that it was the same in a women's 5. Neither were particularly easy to find either.
Hope that goofy answer helps...lol