Welcome to NZWireless!
Any cards with a prism chipset can be found on this wiki entry:
http://www.seattlewireless.net/index.cgi/H...dwareComparison
Shadow has just ordered some 200mw Senao PCMCIA 802.11b cards, but I'm not sure if he has any spare ones. If he has, they are ~$160. Apparently these cards have a very good send/receive sensitivity.
Btw, if you are interested in setting up a public node, consider adding yourself to nodedb (if you haven't already) so that others will know where your node is:
http://www.nodedb.com/newzealand/
Cheers