There are two simple ways to move things from your 2gb card to the new 16gb card....
One, simply hook your phone up to your computer via usb cable, select the drive that is your phone's card and then copy entire thing to a file on your desktop. Then unplug phone, unmount the 2gb card and remove, then insert the new 16gb card and format it via the phone menu. Then hook back to computer and copy that folder you just made onto the new card and you're done.
Two, use some form of card readers to do the same. Just remember to unmount the microsd before removing from phone, and format the new card in FAT32 format.