I believe a fully synthetic oil is what most here have decided is best. Choose a weight based on what the temperatures will be like when you're riding. I chose 5w/40 Rotella full synthetic which I think will be fine for summer or winter here in Georgia, USA. Found it at Wal-Mart.
I just got a two pack of "Hi flow" filters from Scootertrap for $22 bucks delivered.
Then again, now that I think of it, you may be advised not to go to synthetic till more break-in time has gone by. Let some others check in on this topic, please..