You can go to the poly clinic. They have dentist there and subsized as well. However not all polyclinics have the service so it would be good for you to check which is the nearest one available to you. Also they only accept appointments.
Did you check with the doctor why did the antibiotic caused a stain on her teeth? Or could it be something else? Polyclinic have dentist there. Paragon has a few children dentist too.