Spotty iMac WiFi Connection

I just got a new iMac and I am having a hard time with the built in Airport Card. The issue is that I have my iMac and my Powerbook connecting to the same wireless connection and the powerbook has absolutely no problem connecting or staying connected. However, whenever I connect to the wireless network using my iMac the connection goes in and out. When the connection slows down/stops and I check the airport connectivity from the menu bar, it always says "Scanning..." even though it shows maximum bars of connection.

Attached:



Does anyone else have this problem?

Should I take my iMac to the genius bar?