Strong signal but no internet

I am in the CG in Cape May and I have a Inspiron B130. I have had a internet connection till recently. I have a card inthe computer. I dont have a router but was still able to get on until yesterday. Does anyone know how to get it back? Will i have to get my own router? So confused. I would appreciate any help. My roomy has cingular internet with some fancy card. I assume the device at her bed is a router but she has this big card in it. Can anyone help. Don't know why i cant connect. Thanks Nicole