Another that would be good is ¨Man´s Search For Meaning¨ by Victor Frankl. I read it in English but I believe it is also available in Portuguese. Reading a book like that with both translations side by side is a good way to learn.

Night is a good book although it is very sad. I agree with Shukhrat that it would be helpful to read books you've read in Portuguese already. Honestly, it doesn't matter much what you read. Reading is a great way to increase vocabulary.

How about reading those, which you read in your own language?

Other books by Elie Wiesel