Sveti Stefan is 110 kilometers from Dubrovnik. It's takes approximately
1.5 to 2 hours by car(the road is busy, and montenegrian police very strictly controls speed limit). Sarajevo is 300 kilometers from Dubrovnik and it takes 4-5 hours by car, and I recommend going there.
I think there is no ferry service between Albania and Montenegro from Dubrovnik (only domestic lines and few lines to Italy).
If you are interesting in my service don't hesitate to contact me through e-mail and we can discuss everything in details.