[otrs] Getting customer data in to OTRS, fields for address, OS, postcode etc?

Hi, I'm new to OTRS, so please forgive me, I've been using RT for a couple of years but it lacks some features which I hope otrs can help with. I'm currently trying to see how to set up customers (they dont need web access to otrs) in otrs. I can export my tickets from RT and create a CSV with names, email, address etc. Can I import this in to OTRS? Can I then add custom fields, so that when a new customer is added (usually over the phone) I can populate these fields? Many thanks Mike