i have a great guy in puerto plata, electrician, very honest, did many jobs for us.
tony rodriguez, 809 710 8150 or 829 560 8150. miesposo spoke to him today, he could see your place, check things and give you an estimate.
he also said you'd permits from edenorte and possibly ayutamiento (at least this is how it works in POP).
i am sending you a PM too.