How do i effectively treat a cold that has racked my family for a week?

Not much to do: There is an old joke in medicine: if nothing is done for a cold, it lasts a week, but with intensive treatment it goes away in 7 days. All you can do is try to avoid transmitting to family members who don't yet have it (hand washing, alcohol gel, cover sneezes and coughs, no kissing, etc); and use aspirin, decongestants, etc to help control symptoms. Don't waste money on anything else. Good luck!