Update 20120210: changed method of refresh so that an added wireless profile is not required. Moved code to github.
I regularly use a wireless router which does not play nice with macbooks. A solution for some of these issues could be an update of the system or some problem with the configuration of the router. However, that is not the case for the network in question. A dirty but quick solution has been to turn wireless off and back on forcing a DHCP broadcast which revives the connection. You will probably want to be alerted when the network is refreshed so set the code accordingly. Options include audible beep, audible “Network Down”, screen inversion and Growl.