how to get time capsule back on the road

i recently installed mountain lion on my macbook pro. before, when i had snow leopard, whenever i had too much info to back up to the time capsule i changed the configuration to work through exthernet. i tried to do so and i got it disconfigured. when i connect through the exthernet cable the light on the time capsule goes green like it's working, but the computer doesn't seem to recognize it. any help on how to get it runnung again would be much appreciated. sorry for my english, evidently not my native language. thanks