Best way is, : Molim te idemo na cugu, moram ti nešto reći :D

informal: Molim te, možemo li otići na piće da razgovaramo? formal: Molim Vas, možemo li otići na piće da razgovaramo? This is literal translation. Both way is to ask one person. I would rather say: Molim te, možemo li otići na piće i razgovarati? Molim Vas, možemo li otići...

You did the question correctly! :) You can say it in various ways, depending on whom you're talking to and how formal or informal you want to sound. Could you be more specific, so I don't go round too much? :)