What are you eating? I have a large amount of allergy related sinus problems as well, but never any infections...
If you want to try something simple that could help a lot over a few weeks. Try fruit juice drinks; always lemon, but whatever other yellow fruits you want/like.
Avoid as many processed and fast foods as possible.
If you still have problems, try a fast. At least 7 days, preferably more. Some people regularly go 40 days (and one person I know ran a marathon on the last day) without food. Do some research into this.. it'll help clear out anything bad in your body; such as those bacteria that seem to come back after your antibiotics.
You need to remember that antibiotics will also kill your natural defenses against disease. Once they are out of your system, you're pretty well defenseless against anything new coming in. You will need to build up your protection by avoiding antibiotics.. but saying that, sometimes it's unavoidable.
Lemon is a great detoxifyer, as well as producing a more alkaline environment within your body. Bacteria cannot live in these conditions. Watermelon is also good for producing an alkaline environment.