Setting up D-Link DWL-G710 wireless extender

We have some wireless blackspots in our house so I'm trying to set up a wireless range extender. I bought the D-Link DWL-G710 which I imagined would work with my D-Link wireless router (DI624). I can get the computer to talk to the DWL-G710 and run through the set-up wizard but then - nothing. As soon as I remove the ethernet cable the DWL-G710 WLAN light goes out. I have been searching the internet to no avail - all I can glean is that this is an incredibly problematic device. Any help gratefully received. I know it has something to do with assigning static IP addresses but I'm missing some steps.
Thanks!