You should have iTunes loaded on your PC. So plug in the current phone and do a back-up. You can select what to back up and even send your contacts to gmail. Once done connect the new iPhone, iTunes will then say its new and is it a new install or reinstall from back up. Select the reinstall and the new phone will have everything the old one had.
iTunes help will also talk you through the process.
Its very easy to do and FREE!