There are so many ways to say that in English from the United States. Here are two ways that I can think of:
Formal: "Excuse me sir, I am lost, would you give me a ride downtown?"
Informal: "Hey man, I am COMPLETELY lost dude, is there anyway you'd let me hitch a ride downtown with ya?"
What do you think?? :)
In Croatian you can say: "Zdravo, izgubio sam se. Mozete li me povesti do centra grada?"
"Hi sirs! I'm lost! Could you give me a ride to the downtown?"
Olá pessoal! Estou perdido! Vocês poderiam me dar uma carona até o centro da cidade?"