You can't, quite simply. There is such a thing as privacy - and privacy laws protect consumers and mobile phone users from someone simply being able to access their details.
Oh, unless you have a court order.
Think of it this way. Would you want anybody to be able to find our your details just from your mobile number? I certainly wouldn't. That information should be protected, as it is.
There are "reverse phonebooks" available, on CD far as I know for Australia that you can enter the phone number and if the details are public, you can see who owns the number. Fairly sure a guy was selling them on ebay ages ago if you want to try to hunt for them.
just start ringing them at random times... hopefully someone else will eventually pick up there phone, or they'll get sick of calling you... btw if your name starts with an A u might just be getting accidentally called...