netty........difficult question for me to answer on the post that you have given.
12 days of supportive treatment does sound a long time for bacterial bronchitis not to improve and perhaps we are dealing with an allergic problem or more like COPD and only a Respiratory Physician with further tests, can sort that one out.
You mention runny nose and not cough, so i would presume that your nasal problems predominate.In Spain there is a nasal spray which is a decongestant called Respibien...........give it a go.
if your chest and wheezing is the main problem then you will need a steroid inhaler.