Diabetes, High Blood Pressure, Cough. Taken Antibiotic. Feels Weak, Dizzy And Nausea. What Does This Mean?

Hello, my mother was recently detected having diabetes (284) and high blood pressure (220/80) in April, 2012. She had constant cough since the last three months and ate a lot of antibiotics to cure it. We consulted the doctor and he suggested that the cough is because of diabetes. My concern is that though her blood pressure levels and sugar levels have come down a bit due to medications , but the levels are still fluctuating and her cough still persists. She also feels weak, dizzy and nausea throughout the day. We told the same symptoms to the doctor and he said that sugar levels and blood pressure levels will come down gradually. I am a bit confused, should we consult another doctor or we should wait for her blood pressure and sugar levels to come down gradually. Also, I am concerned about her constant cough. Is there something called as diabetic cough? Thanks