wireless internet cutting out

my wireless internet for my new macbook (aprox 1 month ago) it works perfectly for 20-30 minutes but then it cuts out without any warning and the only way to get it working again is to turn on/off the airport. the other wireless laptop in the house works fine as does another computer that runs on wireless.(both windows)

i am using a seimans speedstream 6520 wireless gateway.

same thing happens to mine, no idea whats going on with it. Taked to another mac user today at starbucks, he was complaining about his MB Pro having the same issue. Majority of the time im hard wired to my router.