You can write a simple scripts to copy data from windows machines through samba, with simple command cp perform daily or weekly. One thing I would like to highlight here is the -u parameter. With -u parameter, cp will only perform the copy action if the source file is newer then the destination file.
For example, you have mount your windows drive to /mnt/win/db_svr, and wanna back the entire folder, you can do this.
cp -ruf /mnt/win/db_svr /var/backup/db_svr
For Mounting windows drive through samba, check here.
With r is recursively and f is force, this will perform fine backup, if u put this line into crontab.
But too bad, scp do not have -u option, to do backup of linux, we can use rsync.