You've got a few alternatives. You can hang in here a little while and Tim or someone will tell you how to fix it. As mentioned, you can send it into the factory, warranty or not, and get the other barrel. You can sell it complete or part it out here on the H&R forum classifieds, and you can buy the .223 barrel here also and save the factory turnaround time. Meanwhile, you should read the FAQs at the top if you haven't already. Welcome and good luck.
Pete