As a general rule, fares that allow stopovers are more expensive than those that don't, so expect to pay for it. And in case you were wondering, a stopover package doesn't include hotels etc, that was a promotion that some of the ME airlines were running for a few years. Your best bet is to book this through a travel agent or to use multi-city options online to build in your stopover, but as I said, expect to pay more for the privilege.