It is very straighforward. Ask for the belt for your car. If there is a separate alternator belt, it will be the "auxilliaries" belt, meaning the belt that runs PS and AC, maybe water pump as well. The belt will be less than $30 through a retailer if they have them, I am not sure what dealers charge for belts. THere will be a tensioning bolt on one of the pulleys that allows you to move that pulley in and out to loosen and tighten the belt. Just loosen the bolt and slide the pulley in. Slide the belt over the pulleys, slide the tensioning pulley back out, and tighten. That's it, you can do it in less than five minutes on most cars....
edit..I just searched and didnt find a belt online, contact your dealer and have them sell you one. They will have them in stock.