By testing, do you mean try to establish an internet connection? Sorry, wireless networking is not one of my stronger skills.
Yes. Test with the laptop first. Connect it to the bridge with a cable and disable the wireless connection.
If I remember correctly....
Select client bridge for the wireless mode.
Add your wireless key under security on the client bridge.
I set the local address to something other than the default router ( 192.168.1.200 or something outside of your dhcp range on your main router ) and tape it on a note to the bottom of the router. If you leave it at 192.168.1.1, it won't route correctly.
Setup dhcp relay (enable).
Do a site survey and join your network.
I think thats it.
There are good directions on dd-wrt for your exact model if that doesn't work.