You might want to try Julio Genao, Proprietario, 809 261 3882 or cel 809 232 8703.
En la entrada del Padre Granero, Calle Principal No 12
Peurto Plata.
He made and installed metal gutters for our house here and I know of a number of other places he has installed them. Not the cheapest around but reliable and they have lasted well. He can make them in the colour (painted) you want and they are in general made out of thin galvanised steel sheet. He may make them in other metals but I dont know about that for sure.
HTH
Olly