spicyayam wroteIf you are only spending 2 months here you can get a 60 tourist visa at an Indonesian consulate/embassy or get the Visa on Arrival (30 days) and extend it for another 30 days.
I'd suggest NOT to get the Visa on Arrival and then extend it, unless you want to make 4 trips to immigration. A friend has just extended her 30 day VOA for another month and yes, 4 trips to immigration to complete the process. Also, Immigration will only process documents between 8:00 am and 12:00 noon.
Best to get a 60 day tourist visa from the Indonesian Consulate in your home town. You don't need a sponsor for this, just a photo, evidence of return ticket or ticket out of the country and your passport. You will need to complete a form obtained from the Consulate and pay the fee (in Australia it's AU$60.00). Processing time depends on the State in which you apply but 3 to 5 working days is normal.