I suggest a cronjob using scp to copy files.
Write a shellscript backupToServer.sh, which tars your files-to-backup and then puts them on the server with scp /path/to/backup/tar user@server:/path/where/backup/is/stored. make usage of ssh-keys.
You can use date or similar tools to name your backup correctly.
With crontab -e you add a new cronjob. Take a look at the time settings of crontab, they are rather trivial but look weird on first sight.