Cron sending reports weekly
You can set up cron jobs besides the main one driving all the scheduled jobs on the Scheduled Jobs page.  The way to do it is explained at http://wiki.civicrm.org/confluence/display/CRMDOC/Managing+Scheduled+Jobs#ManagingScheduledJobs-PHPclimethod

You might have your main job going every 10 minutes like:

*/10 * * * * php /path/to/civicrm/bin/cli.php -s site -u user -p password -e Job -a execute


You'll just need to add a new one for the report, let's say to send the report instance with the ID of 123 every Monday at 8:00:

0 8 * * 1 php /path/to/civicrm/bin/cli.php -s site -u user -p password -e Job -a mail_report --instanceId=123


You don't need anything in the main Scheduled Jobs page for this--this is 100% separate.

Back in the old days, this is how you had to do all scheduled jobs!  Uphill--both ways!