Here is my translation at last! I finally realized that part of my problem was the poor transcription of the lyrics in Portuguese in the version I was trying to translate. Because of that I tried to make appropriate adjustments through a combination of lyrics taken from other texts. I also attempted to correct the punctuation; but may have missed something. I should point out that the first link Masato gave to an English translation contained a very good one (quite nearly literal) but it lacked some of the lyrics shown on other sites. This translation is also not entirely literal because such a thing would make no sense at all. However, I have tried to stay true to the Portuguese insomuch as is possible. I should inject some sort of disclaimer here as to the accuracy of my translation; but it was as good as I could do.

Manhã de Carnaval
Morning of Carnaval

Manhã tão bonita - manhã
Morning, so beautiful - morning
De um dia feliz que chegou
Of a joyful day that the sun
O sol neceu surgiu
Arrived (re)born
E em cada cor brilhou
And in each color shone
Voltou o sonho entao
The dream returned
Ao coração
To the heart

Depois deste dia feliz
After this day of joy
Nao sei se outro dia haverá
I don't know what another day might have
É nossa amanhã
It is our tomorrow
Tão bela a final manhã
What a lovely last morning
De carnaval
Of carnaval

Manhã, tão bonita - manhã
Morning, so beautiful - morning
Na vida uma nova canção
In the life of a new song
Cantando só (de) teus olhos,
Singing only of your eyes
Teu riso, e tuas mãos
Your smile, your hands
Pois há de haver um dia
And so, there must be a day
Em que virás
In which you will see

Das cordas do meu violão
From the strings of my guitar
Que so teu amor procurou
That only your love sought
Vem uma voz falar
Comes a voice to speak
Dos beijos perdidos
Of the kisses lost
Nos lábios teus
In your lips

Canta-o-meu- coração
My heart sings
Alegria-voltou-tao-feliz
Happiness returned, such joy
A manhã-deste-amor...
To the morning of this love