Simply sending a Job Summary Report by email does not require a workflow.
If this is the only thing you're doing in the WF, just schedule a report and have it emailed.
If you want to customize the layout of a report, or report some extra information on it, look at a custom report from the Web Console. http://documentation.commvault.com/commvault/v11/article?p=features/reports/custom/t_rptbyo_building_reports.htm
If you, for some reason, really require this information in the Workflow engine, the easiest way I can think of is use the CommCell Console, configure the report as you want. Select Save, and Save as Script.
Then you get a XML file which you can use in qoperation execute (not qoperation report). This would allow you to write the report to a local file on the WF Engine server.
There are other appoaches to do this, but this seams the cleanest.
However, first of all, rethink whether you actually need the workflow engine.