Welcome! Sorry to hear of the stolen Handi. You'll want an SB2 rifle frame with a serial number prefix of NN or HN or later, please see the build year info in the FAQs and Help sticky. There's no guarantee your barrels will fit, they are individually fitted at the factory, but there are do-it-yourself fitting instructions in the FAQs. You can't order a frame from H&R, you'll have to buy a used one somewhere or another complete rifle, seems to me there may be a frame in the NEF Classifieds right now.
Tim