I would use a much stronger strength probiotic than inner health plus. Get a powder and mix it with something or just pop it in her mouth. My 18 month old has been having baby biotic powder straight off a spoon since 7 months old.

I would give her the probiotic as many times a day as the antibiotic and space them as far apart as possible so that the antibiotic doesn't kill off all the probiotic bacteria straight away.