Originally Posted by Laurent B
Another alternative is to use a separate NTFS data partition.
A third alternative is to install a tool into Windows to read ext file systems:
I see from the output of those commands, that your computer sees not only the drive, but also the NTFS partition with Windows. But there are no labels.
In the file browser (I guess you use Thunar), there is usually a pane at the left side, where you can see available partitions (including your Windows partition). If you click on it, it should be mounted (and visible in the file browser as well as with the command df).
Things will be easier if you add labels to your partitions. Use easy-to-understand labels: for example windows for the windows partition.
You can edit partitions with the command line tool tune2fs,
sudo tune2fs -L windows /dev/sda1