Since nobody else has replied here, I'll add what I know, even though it's months later.
To the best of my knowledge, it can't be done. Here's why. 3Com didn't actually implement a proper PCMCIA slot into the Audrey, as it was never intended to be used for expansion. They included just enough hardware to connect to be able to read/write to a CF card, but all the interface is done by the uP, not by a normal interface chip. Consequently, it is just barely possible to mount a CF card as an expansion drive (and it has been done, with the limit that you can only access 1 file), but it's really not possible to use any other types of hardware.
The USB bus is not much better. I don't know of anyone who's been able to mount a wireless USB adaptor directly either. Everyone I know who's using wireless (myself included) goes from a supported USB/Ethernet adaptor to an AP such as the WAP11 or similar