I believe it was recently produced Off-Broadway under the title Cafe a Go-Go, if I remember correctly. The only way I know would be to rent the score from whoever has the US rights to the show, which is very expensive. Except for the Off-Broadway production, I'm not familiar with any other US production of the show. Very few know it.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian