From Bern there is daily bus to Pozega most days of the year, the bus goes via Zurich and Zagreb where passengers have to change bus, use date field above to see timetable for a specific travel date. The travel time from Bern to Pozega is about 19 hours. If you plan to travel back to Bern you should buy a return ticket which is about 20% cheaper then two single tickets, departure times for the returning bus from Pozega you can see here