Actually, I think Saramago
is the only translated Portuguese writer
Saramago has the luck of having a wife who owns a prominent Spanish publishing house that promotes his work all over the world; Pilar, to whom all Saramago novels are dedicated, also translates his work into Spanish herself. Saramago, at the time of his Nobel Prize victory, joked that Portugal didn't lack Nobel-worthy writers, it just lacked good promotion beyond borders. I think that's pretty true.
Anyway, you might be lucky with these:
Miguel Torga (you'll probably find one of his collecitions of short-stories around)
António Lobo Antunes (considered Saramago's arch-rival)
António Damásio (non-fiction; he wrote the famous
Descarte's Error)
Luís de Camões (our great epic poet; every country has one, I guess)
Eça de Queiroz (19th naturalist novelist, in his time he was considered better than Flaubert, if that means something to you
)
Eugénio de Andrade (great modern poet)
Fernando Pessoa (greatest poet of the 20th century)
Alberto Caeiro (Pessoa's teacher, my favourite Portuguese poet)
Ricardo Reis (early 20th century poet who wrote in the Classicist tradition)
Álvaro de Campos (another early 20th century poet, wrote in the futurist tradition
Bernardo Soares (undefinable nutcase; his only book,
The Book of Disquiet, is brilliant; one of Europe's forgotten masterpieces)
If the discrepancy between poets and novelists seems strange, it's because the Portuguese are really a lot better at poetry than prose.
However, I suggest you just learn Portuguese; otherwise you'll be dead before the really good stuff gets translated into English.