Please see the recent post by kalamate
You will need to do a cronjob, type man crontab at your linux prompt for details. and schedule a mysqldump operation. See the mysql documentation for details of mysqldump
Then you will need to tar or bzip2 the file system, Again see the necessary man pages for each for parameters.
This is the procedure I use for all hosting accounts on tikihost.net servers.
If your on Windows, then you'll have to wait for a windows user to answer, My knowledge of windows consists of using Scheduled Tasks, a batch file to mysqldump, then the DOS version of pkzip to archive the tree.