B43 roaming issues

I'm on a horrible network, there aren't nearly enough access points for all the clients on it, but there's nothing I can do about it. The issue that I'm having with it is that my card will roam between the access points as expected for a while, then suddenly drop the connection and not be able to connect again. If I disable wireless, then turn it back on it will connect instantly. If I don't it will retry until it times out. I have also noticed that if I run iwlist scan not all the access points that should show up do show up. Sometimes the ESSID of the network isn't listed at all, and sometimes 3 BSSIDs for the network are listed. I'm not sure what's going on here.

I'm using network-manager, b43 drivers, and kernel 3.8.4-202. Any ideas or solutions? There is no encryption on the network, just a MAC address filter. Thanks.