Works great, then peters out or stops working completely

My boss and I are connected to the same Comcast wifi network at her house. I'm working on a 15" Macbook Pro I bought this summer. She is working on a 13" Macbook Pro she bought couple years ago. Her internet seems to work fine all the time. I'm not sure how many bars she typically has but I think it's 3 or 4. Right now she has 4 bars and I have 2. Mine works sporadically. I normally have about 2 bars, sometimes 0. Webpages never give the failure to load--they just.. don't load (same with uploads and downloads). If I turn off airport and wait two minutes or so, and turn it back on, then the internet works or even works great for either a very short period (say seconds to a minute) or for several hours. Overall the internet seems to work about 1/2 the time, maybe a little more. Any ideas? I figured my having a newer computer would mean I wouldn't have a worse connection than my boss. We both are running OS 10.6.8

How do I delete the linksys connection and re-add it?

System Preferences - Network - hifi highlighted on left - click Advanced button - remove the network from the Preferred Networks box by highlighting it, then clicking the minus button below.

Add a network by clicking the plus button.

Once I start having issues, I usually just go ahead and remove all the networks listed there and then add them back one at a time as I rejoin them.

I deleted the connection and re-added it but it did not improve things at all. Any ideas why my boss' connection would be better than mine?