We had thrush for 10 weeks we were on nystatin I was on an oral anti yeast pill. We tried EVERYTHING! All the tricks of fresh air, new bras, everything. Here is what finally worked: Grape Fruit Seed Extract. My cousin kept telling me about it but I blew her off a few times. Until we had seen the lactation consultant, my MW, her ped, and they just starting telling me that some people have in until they wean.
This is the treatment plan I followed, and it literally was TOTALLY gone in 3 days, after having had it for 10 weeks! http://drjaygordon.com/breastfeeding/thrush.html. You can also add it to your dishwater to wash bottles and your laundry to wash bras, clothes with spit up etc. I didn't but you can. Good luck I really recommend trying it. I tell everyone about it!