My wi-fi connection at the top keeps looking for networks, I get disconnected from the internet and have to wait until he finds my network. Any help appreciated.

My airport express doesn't seem to be working all of the time. I use Exede and have my airport express connected to their box but when I try to get on the internet my wi-fi connection at the top of the page says looking for networks. I have bypassed the airport express and connected the ethernet connection directly to the back of my Mac and the internet works fine. Anyone have any ideas on what my problem may be. I am not a computer wiz, so bear with me..Thank you..Jay