How to keep my messages when I change phone?

Hi, I had nokia 7390 in which I have collected many many messages from my fiance. But this nokia is not repairable, it is gone completely bonkers. I used nokia bl-5ca while I was sparing money to buy new phone. I bought another nokia 7390 and when I open folder saved messages or inbox I don't see my old messages. In 'sim messages' there are messages I received while using the nokia bl-5ca. I don't want to lose all the messages I had. Can you tell me how can I save them?