Expanding Wireless Network w/AirPort Express?

Hey folks. I bought an AirPort Express under the impression that I could use it to boost the signal on my already existing wireless network (not AirPort). We recently moved to a bigger house with more walls and electronics, so the wireless network gets weak in the farther areas of the house. The router is right in the center of the house, so that's not an issue...it's just my bedroom is on the outer edge in the back of the house. Anyway, I thought that AirPort Express could be used as a sort of way station, so to speak, between the router and my computer to boost the signal. I see a way in AirPort Utility to do just that if I connect the AirPort Express to a wired ethernet...but that kind of defeats the purpose of a WiFi network, doesn't it? Is there any way to use the AirPort Express as a wireless network booster without connecting it with Ethernet cables?? Any help is appreciated.

I have just answered this question for someone else

From my website WDS

Extending a network to more than one airport device using WDS

In the Airport utility select the main device

Under the TAB [Wireless] change the Wireless mode to “Participate in a WDS network” and make sure “Allow this network to be extended” is selected.

Under TAB [WDS] on the main device change the [WDS Mode] to “WDS main” and click “Allow wireless clients” then add the hardware address of your 2nd device/3rd device into the WDS Remotes list by clicking on the [+] button and typing the hardware address

Now in the Airport utility select the 2nd device

Under the TAB [Base Station] set all the information the same as the main device other than the [Airport Express Name]

Under the TAB [Wireless] set all the information the same as the main device.

Under the TAB [WDS] change the [WDS mode] to “WDS remote” and click [Allow wireless clients] then type the hardware address of the main device into [WDS Main].

Your network will now extend to the 2nd device automatically

AFAIK you can only extend the wireless range of an Airport device with another Airport device.

Haven't tried it myself, but if you use Airport Utility and open your Express, see if you can get it to join the existing non-Airport wireless, but I doubt it will work as I believe there are Apple-specific protocols that get it to share the wireless connection between devices.

Please report back with your results.

Ok, I got as far as "then add the hardware address of your 2nd device/3rd device into the WDS Remots list..." What's the hardware address? And what are my 1st, 2nd, 3rd, etc. devices? A quick run-down: We have a wireless router (not AirPort) in the hall closet hooked to a cable modem and to the ethernet in the rest of the house. The ethernet is connected to the iMac in the study and the MacBook Pro in my room (which is a new development since the original post...I had the technician come out and wire my bedroom). I want to put my AirPort Express in the kitchen, which is sort of centrally located, so as to extend the wireless network. Thanks for your help.

The hardware address is the MAC ID on the wireless device. On the router you'll have three, one for wireless, one for LAN and one for WAN. You'll want the wireless MAC ID.
Looks like 00:00:00:00:00:00 or it could be 12 characters run together. They're in hexadecimal format. ie: 0A:33:A5:09:B4:33 or 0A33A509B433

Well, I give up. Actually, the ethernet cable has been connected now, so I no longer need this problem fixed, but I tried it just for S's and G's...and it appears that my wireless router has to be an Apple device. Either that or I'm not doing it right. I do appreciate your help, Cow and Ian, and hopefully this thread will be able to help someone else, but I no longer need it. Thanks.