If its a remote service shouldnt they be backing up the disk? All I do is backup the data (files and database) and have a copy of the settings. If the disk fails they will not let you restore it by yourself anyway.
For a simple way on ubuntu, do some research on 'lftp' - its a command line ftp client that reads instructions from a text script. Write the script and run it as a cron job on your laptop to do the sync. The script you write can login via SFTP (uses ssh - no need for the server to run a dedicated FTP daemon) mirror the files you want and exit in about 3 lines of script. The cool thing abut this way is that you already have the software on the server (ssh) to do it (unless you are using telnet or something daft like that!).
It will be difficult to run this from the server end as your laptop might not be connected when the server wants to backup. Easier to PULL data on these occasions than PUSH it