'advice' is uncountable in English. If you gave him just one, you should say a piece of advice.
English grammar is weird. See e.g. http://dictionary.cambridge.org/grammar/british-grammar/about-nouns/nouns-countable-and-uncountable
PS they also say some advice.
So what nouns/concepts can be 'gott' but not 'bra'? So far it seems like food, people (especially leaders and Gods), and advice.
The last word "råd" sounds wrong to me both in fast and slow speech. Something like "ro" or "rum".
It seems like the sentence is written to force a parallel part-of-speech correlation between Swedish and English. In Swedish råd is countable; in English advice is not. As seen in Google Translate, a strict word-for-word matching ignores the fundamental structural differences between languages and makes people into poor speakers of acquired languages. (My opinion.)
I don't disagree per se, but you're still making the assumption that the usage is wrong. The object of this exercise is to teach 1) that råd is countable in Swedish but not in English - hence "a piece of", and 2) the idiomatic phrase ett gott råd. We'd lose both if we changed the default translation.