remote desktop wireless lan losing connection

I have a problem connecting to my laptop which is running Vista 5308 when it's connected to the LAN via wireless (no problems when its wired).
During the connection process the laptop is dropped from the network, can't ping it and the remote desktop connection is lost, it never completes the logon process although the laptop screen indicates that a user is "logged on remotely from...."
I have to log back on to the laptop to get the wireless connection active again.
Anyone any ideas, the card is an internal "Wireless CB54G3/MP54G3 Wireless LAN Card" using the driver as installed by Vista.
Cary.