Airport does not work

I have a white macbook core duo, and my computer won't connect through wifi. I can only stay connected to my wi-fi base (or any other base) for literally 10 minutes before it loses the signal and attempts to find it again. Every other wifi device in my house works perfectly too. This problem has started occurring about 4 Months after installing snow leopard if it helps. So i am wondering, do i have to replace the airport card, or is this a software related issue?