Wireless dropping Router

[Jim]

FC18/KDE , I can no longer update F18 any more

I have a Dell D600 Latitude that is dropping the router dd-wrt. Wireless 
networking is okay for about 20- 30 minutes before it drops

If I try to reconnect Wlan0 and Connections there is no dd-wrt router 
shown in Connections to connect to.

I have to restart the Laptop to get dd-wrt router to show up in Network 
Connections so I can reconnect.

The wireless card on laptop uses the b43legacy driver

The wireless card is a   Broadcom  BCM4306