You can take amoxicillin
and clavulinic acid combination drug as it is the first line medicine for sinus infections.Secondly you can take decongestants both oral and nasal as without decongestant there will be no use of antibiotics .
You should get done CT scan
of nose and paranasal sinuses
to see for the extent of sinus involvement and disease.Then if required nasal steroids
can be given with normal saline nasal sprays.
Urinating every 4 hrs is ok depending on the weather and amount of fluid intake.