Unless you have insurance, the only way to get a new phone is to buy one either at a store or order one online. If you buy from ATT, it should come with a SIM card set up with your same number. If not or if you buy from some other source, take it to any ATT corporate store and they will provide a SIM card for free.
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.