Hello,
Velero beach, is it in Cabarete on the north coast? If it is, the closest diving is in Sosua, about 15 minutes drive, there is no diving from Cabarete itself - no motor boats allowed by Cabarete beaches.
A good dive shop is Northern Coast diving, ran by Mark - an American guy or Merlin ran by Jurgen - a German. Both are very good dive shops. I helped them with diving for 2 years while I was living in Cabarete.
If you haven't booked your hotel and don't like windy conditions and wavy oceans (great place for kiting and surfing though), you should consider starting to dive on the couth coast, where the Caribbean water are much much calmer.