Antibiotics will treat either "gram positive" infection or "gram negative" infections. If you google the antibiotic you're using you shouldbe able to figure out if its for gram positive or negative, and then google which antibiotic would treat the opposite type of infection. Most of the water antibiotics in the feed store are made to treat a very wide range of infection types, but you can probably just change it up.
The ideal thing to do would be to get an injectable from someplace like valley vet or randall burkey.
there is a "chicken Dr" working at one of the places named Brown:
http://www.firststatevetsupply.com/
and he consults over the phone. If you tell him which antibiotic you're using, he may be able to suggest another one. I hear that he knows his stuff and his place sells the meds over the internet. Its pretty reasonable.
But you may be able to google this and figure out what to try.
even with alot of expensive smears its not always possible for a vet to diagnose the type of infection, especially after treatment with a broad spectrum antibiotic.
Whatever you do, keep up the good work and just keep on....it could be that its just going to take her body some time to throw off the infection...but do keep up hot compresses and try to get the smelly stuff out to help her out.
also try to feed her some scrambled eggs and yogurt to help her body get stronger and rebuild its enzymes.