I know exactly where it is,
at Avenida Ana Costa and the beach. We lived farther north, just south of the Ponta da Praia disctrict for 2 1/2 years, and then south of there, near where the town of Sao Vicente began.
If you go to the Orquedario, you will be one block from where I went to school for two years. The first time I summoned enough courage to hold a girl's hand was in the Orquedario :)--and yes, it is an orchid park.
Ron