I don't have an expiration date on mine and I haven't called to ask.
For someone else, when I went to look at it closer, it does say that you can turn this "hotwire" deal into a package, and yes you have to pay the whole thing, and no you don't get any part of it back if you cancel the package. From the fine print:
Payment Procedures You will not be provided with a list of Resort hotels to choose from prior to payment. Immediately after booking and full payment, Disney will inform you of the name of the specific Walt Disney World® Resort hotel and the room type booked. Full payment of the entire package is due to Walt Disney Travel Co., Inc. (Disney) at time of booking. Receipt of travel documents by guest is proof of full payment and, therefore, no other confirmation of receipt of full payment will be sent.
Cancellation, Changes and Refunds Prior to Guest Arrival
The reservation is non-refundable (except for vacation insurance cancelled within 14 days of booking as specifically provided below), non-cancellable, non-transferable and non-changeable. Cancellation fee is equal to the entire reservation amount. Credit will not be given for unused reservations and cannot be used toward the purchase of any future reservations. All airline tickets included in this package are non-refundable. The cancellation fee is equal to the entire ticket price and cancellation and any credits that may be issued by the airline are subject to the applicable airlines policies. Land portions of the reservation cannot be canceled without also canceling the air portion of the reservation booked through Disney. Vacation insurance is nonrefundable if not canceled within 14 days after booking reservation. For reservations made 14 days or less prior to guest arrival, vacation insurance is nonrefundable if not canceled at least one day prior to guest arrival. Changes, including but not limited to, changes to type of package and package components, the Resort hotel, room type, name on the reservation or travel dates, are not allowed.