You can't make a wireless bridge with only two DIR-655s. Doesn't work that way. You can wire up two DIR-655s on opposite ends of your home and make them work as one, but only because they're wired into each other's switches.
So, to answer your question on how to bridge it wirelessly, get a DAP-1522.
http://dlink.com/products/?sec=1&pid=663
Your Setup would look like:
(Cable/DSL Modem)<-Wired->(DIR-655) <-Wireless-N-> (DAP-1522)<-Wired->(DIR-655)<-Wireless-N->
I'm no ASCII artist, but it should give you an idea of how to do it.