how to configure an alfa wireless-g ethernet router/bridge?

i'm preparing to connect a two-computer home network to a wireless isp that is not yet on the air. both computers are xp sp2. they are currently connected to an ethernet router that is fed by a microwave internet service that will soon disappear. i want to connect to a wireless isp and have the box that does that connect to the two computers via ethernet. there is currently a wireless access point connected to the router. either computer will utilize this for internet access if reconfigured to do so. i'm using this netgear access point to test the alfa router.

the alfa aip-w610h router connects to the above wireless access point; it's "status" page shows the connection. an xp sp2 computer, ethernet connected to the alfa router's lan port, can ping the router. but a browser on the computer cannot display a web address; there is a timeout message.

if the computer's built in wireless adapter is connected to the access point, no problem with internet access.

i need help figuring out where the data-transfer breakdown occurs. an ip address wrong somewhere? any help you can offer this network neophyte will be appreciated.