You don't actually need a SD card to transfer files. While a card can be moved from one device to another, it isn't really recommended as it can easily lead to damage to the SD card itself, and possible damage to the ports on each device.
The simplest way to transfer files between a device (phone, tablet, MP3 player, etc.) to a computer is to connect the device to the computer via USB cord. You should then be able to access the file system on the device through Windows and transfer files back and forth.