Lion Upgrade Connection Timeouts on Wifi

I just upgraded my 2009 MBP from Snow Leopard to Lion. Immediately following and ever since, I get a connection timeout on my wireless internet about every 2-3 hours. I have to reset the cable modem and wireless router for it to work another 2-3 hours. I do this everyday, all day, in order to be able to work from home. Our internet provider has checked and it's not a problem on their end. My husband has a PC and it affects him too. However, when I went on vacation for a week, he told me he had no problems with the wifi and never had to reset it - so I know it's my MBP causing the problem. I have a feeling a setting was switched somewhere when I upgraded. Anyone have any suggestions?