"Necesito un carro para ir a la librería."
Translation:I need a car in order to go to the bookstore.
Yes, I was tempted to say "library" even though I knew that "biblioteca" was the word for "library."
"In order to" seems a bit wordy. This could be left out and the sentence would mean the same thing and sound more natural. I haven't tested to see if Duolingo would accept.