the second pair is usually the yellow and black if standard conventions were followed. The telco may require you to connect to a new Network Interface Device (NID) which may involve extending the yellow black pair from the existing point where they connect to the existing NID.
Or, just ask the telco to activate the service at the existing NID, or new NID, and label it then just run some phone wire to a new jack. Use a cordless set to minimize the wire you need to run.
OR, just use cell phones!!! That is absolutely what I would do, especially if this were a temporary living situation.