Losing Internet connection

Hi,
I just bought the 2.16 macbook and since i brought it home when the computer goes to sleep it loses its connection to the internet and the only way to get it back is to restart the machine or go into the newtork icon under system preferences and run assist me. I am running leopard. I even tried switching my router to an airport one. That didn't help. So i returned to the linksys router i was using and got the firmware update. Any news on how to fix this problem. I called apple care but that didin't seem to help.

THanks

so...you have a wireless connection? and you are connecting to what kind of internet service?

I have cable modem through time warner