Take a bus to San Jorge, Rivas, then take one of the boats to the island of Ometepe and board the first bus to take you to Altagracia.
Bus Schedule - Isla de Ometepe
10:30 am, 02:00 pm, 03:30 pm, 04:30 pm
Buses take Moyogalpa - Altagracia
Another option is to use private transport
Taxi Moyogalpa - Altagracia
For our part we have new, air conditioned minibus (15 passengers)