No directly via Tokopedia and a courier won't work and they won't allow it. Tokopedia contains the track and trace information. Which obviously doesn't support international shipments. That's also the reason why many auction and sales sites (as Catawiki) refuse customers in countries as Indonesia; the track & trace information is not integrated, the systems have no interface.
So only if you bypass them and make a deal directly with the seller, it would work.
And for an expensive item I would never do that here unless you can use a rather 'safe' system as PayPal. But no seller here will agree to that, they want a bank transfer.
If you'd consider dealing directly with the seller anyway, take the Indonesian Pos / EMS, they also offer track and trace. DHL c.s. will screw you, burden the seller with a lot of administrative requests and make sure you pay excessive customs. Besides the fact they are amazingly expensive.