What medicines can I use for bronchitis?

What OVER THE COUNTER medicines can I use? And how can I be sure this is what I have(without seeing a doctor) ..My reasoning for thinking it IS bronchitis, is because I am an ex-smoker of a couple years.. recently I started smoking like 1 cigarette a day (newports) ..and when I work out at my friends house, I am exposed to second hand smoke (about 2 to 3 times a week) ..i started smoking the cigarettes a few months ago. I started having a weak dry cough which now this evening has turned into a hacking cough and im hackin gup greenish stuff. Pretty sure its bronchitis? what can I buy?