I'm sorry, I don't know what to tell you. Many places here in the U.S. we cannot buy antibiotics, without seeing a vet. In some states they are still available, depends on where your uncle lives. my guess is by the time he buys something, and ships it to you( if that is even possible) your chick will either have recovered or passed on. Right now, I'd try maybe child or baby vitamins to boost her system, keep her warm and hope for the best. Maybe someone else here has some better ideas.
You did your best. Chicks can be so fragile sometimes...
