get the shipping adress,
box everything up and go to your local post office and ask them for quotes
fist class / air
and econemy / sea
sea is usualy a 1 third the price for air, but can take up to 3 months to arive,
once you have the quotes from the post office you can discuess with your buyer how to proceed.
also its a good idea to note down the dimentions and wieght of the parcle just incase they pull from the sale, that way you have it on hand and can just call a OP for quotes if selling to another country
hop it helps