This might not be the best place to ask, as few adoptees have responded in the forum as far as I know.
However, for what it's worth, I think you and your match will just have to go on plugging away at it, hoping for further shared matches with same background/place/name where given.
As so few matches at Ancestry seem to have trees, this may be a protracted process.
It is perhaps of more importance to her and her father than you, and you may never find out exactly who his parents were, but it is a start. As more and more people get tested, one day you may find first or second cousins to narrow it down a bit further.
Uploading the DNA of all of you to other sites will show you exactly where you match and could give extra shared matches, could be very helpful.
Good luck, Margaret