Create a relationship from Report to History that is sorted descending by installedDate, and put a one-row portal into that relationship on your layout. (Or use an existing relationship and sort the portal.)
If the relationship is sorted correctly, you could simply put the fields on the layout without using a portal.
Thanks so much for pointing me in the right direction!
I created a table occurence for the tblReportHistory table.
Then used a descending sort on the ReportHistory_InstalledDate on the relationship between tblReport and tblReportHistory.
And used the "tblReport" table as the main table for the Layout.