Have u tried steam vaporisers for some sinus relief and cleansing? If u don't have one then u can always pour boiling water into a shallow bucket/lge bowl, put some eucalyptus or lavender oil in (just check what oils are safe in pg with chemist) and hold a towel over u and bowl taking in deep breaths of the steam. Just be careful not to overheat
Also garlic and ecanacia (sp?) herbal tablets are really good to ward off nasty germs.

Sorry i can't be of too much help - hope this cold finally leaves u alone soon