As the sd card uses a Linux partition, you can probably just install a Windows driver that lets you read and write on such a partition. I haven't tried recalbox yet, but for ext3 or ext4 drives I have used succesfully ext2fsd
Read this :

Or just download and install
Reboot your PC and insert your sd card.
Don't forget to eject your sd card from Windows when you have finished to copy your files.