A culture would be appropriate, but in many of todays hospitals they just don't do them. Or at least not without a lot of pushing and shoving. It would great if we would go back to the old ways sometimes, which were not necessarily bad ways.
What I would do is go back to your doctor, perhaps have more tests regarding your sinuses or lungs depending on what he or she finds during your exam...perhaps get a culture to see if indeed that is the right antibiotic to treat that particular infection. This sinuses could be dripping back into your throat, causing the congestion. Whatever the cause for your continued problems, your doc needs to be contacted so that the proper tests can be run. Make sure he or she does a culture of your sputum to see what is growing in there. A culture also provides invaluble information regarding what kind of antibiotics that would be most effective in treating the infection. It sounds like the Augmentin didn't do a very thorough job in clearing your sinusitis. Hopefully you get some relief and answers soon...Sunny.
Sounds like you have pneumonia. If I was at Las Vegas, I'd bet my airplane on it. I suspect the AMOX is not doing any good if you still have the problem. Suggest your physician prescribe Cipro.
I have the same almost exact problem; have you had any luck yet with it?