I am addressing the problem by getting a NetGear 802.11b Wireless Access Point (100 quid + VAT) and plugging the Receiver into that. Then getting a PCI 802.11b card for my server and letting it do the routing to my main Ethernet network.

Kind of a strange way of approaching it, but it is much cheaper that an Ethernet- 802.11b converter, which is silly because the access point is probably more complex...