Write to, or go and ask someone at the Opera house, or someone having to do with the producition if a libretto is available for sale. If it isn't, probably the only place you can find it is in the printed vocal score.
There's a pdf floating around somewhere online but if you just want to read the 165 lines you can find it here: http://www.damoreadjusters.com/resources/nysf
The New York Shakespeare Festival, now called The Public Theater, calls its performances of Shakespeare in Central Park, "Shakespeare in the Park" although that name is used for outdoor Shakespeare productions around the world. NYSF put on Othello in 1964 with James Earl Jones in the title role. It would appear that Joseph Papp (the push behind the company) was the director, although the references are not clear.
The New York Shakespeare Festival made the outdoor Delacorte Theatre in Central Park famous by its presentations of free Shakespeare performances there. Indeed Shakespeare is often performed in outdoor venues, so there are probably a number of theatres (most less famous than the Delacorte) and companies (most less famous than the NYSF) who might fit this bill.