Well I tried using a natural oil called neem, and rubbed a little bit under my nose. Wow, just the smell of it cleared my sinus out quick. I also made an infusion of dried chamomile flowers and fresh ginger to sip. It seemed to help loosen up the congestion. It maybe worth a try.
1 Tb of Chamomile flowers
2 chunks of fresh ginger
1 tsp of whey low to taste
3 cups of water
I got my first sinus infection in the sinuses in the back of your head? about 2 years ago now...it lasted 6 months..that was with antibiotics. the only thing that finally cleared them out was sitting over a large bowl of almost boiling water with a bit of vicks (not sure if u have that over there but its just a rub on cream for the chest to clear it out) in it anbd a tea towel over my head....and then i just blew my nose until it hurt..i did it about 4 times a day every day for a week. not sure if that will help you though!