Aorport Expresse getting Worn of?????

I use my Airport Express for my Internet connections and for Airtunes music streaming. We do that for over a year now with no problems since a few months. At first there was an occasional drop of connection, but it's getting worse. Is it because Snow Leopard, my daughter got an iMac so we have 2 iMacs, 2 iBooks, 2 iPhones and an iPod touch connecting through it. But it is so worse that when i get some big data streams through it (coping from one to another comp., or Music streaming it cut's out very fast. Sometimes when the traffic in our house is high, already when somebody opens a new webpage, so it seams at least. I tried resetting, other channels, other cables, another electrical outlet, another router. Disabling other wireless devices such as DEC telephones etc, but it is still happening and getting worse. Al the time i have the Airport i have used it heavily, almost always ongoing, so i thought, could it been worn out, because i can not think of another solution and i'm sure it is the Airport that is the culprit. Could it be. I think i'm going to buy a time capsule for the heavy use and hope that the express is at least giving me the Airtunes function.