Hello Upendra,
Conga Composer doesn’t support joined reports, it supports the use of up to 50 unique Salesforce Reports or SOQL Queries as data sets in a single merge process. It sounds like you can’t include both of your target objects in a non-joined report, so I’d recommend using 2 separate reports that span the respective Account->Acts and SP->Trgt relationships and then including both reports in your Conga Composer button URL. The parameter syntax will look a little something like:
&ReportID=[Your1stAliasGoesHere]00Oxxxxxxxxxxxx,[Your2ndAliasGoesHere]00Oxxxxxxxxxxxx
This article in our KnowledgeBase explains how to add reports to a button URL: Click here
I hope this helps, but please feel free to contact our support team at any time to get hands-on assistance with your solution: https://support.getconga.com/