Kathleen, this still sounds like thrush to me. Sometimes it can very
persistent, despite treatment.
You said the baby still has oral thrush: so the baby needs more intensive
treatment, eg nystatin drops after every feed instead of  4 times a day, and
perhaps applied with a piece of gauze onto thrush areas (so the drops are
not simply spat out or swallowed). Does the baby still have thrush in the
nappy area?
The mother needs more topical medication too, eg gentian violet or nystatin
ointment.
She should continue oral medication, but if fluconazole is not possible, I
would use oral nystatin ii caps 3 or 4 times a day. It is not well absorbed
like fluconazole, but I usually get good results with it, and it is much
cheaper and is known to be safe in lactation.
Regarding her diet: she should avoid alcohol, dried fruit, peanuts, grapes
and yeast as well as avoiding sugar.
Many women find they experience less pain if they express rather than
feeding, so she might want a "break" by expressing for a day or so, or
expressing in the evening if that is when the pain is worst.
Good luck,
Lisa Amir
GP / LC in Melbourne, Australia