You can find all information about public transport on the following Rimini Tourist Office website and here the map.
The public system is integrated with Google Maps.
Within the city of Rimini the price for a ticket is 1.30 EUR (2 EUR on the bus), the ticket last 75 minutes and you can take as many buses as you want.
There is also a SmartPass where you have free rides for 3 or 7 days.
More information on how to get around in Rimini can be found here.
There is a car park inside the Venue, but the cost is not included in the conference ticket: