You can use Aspose.Slides for JasperReports to export data directly to a PowerPoint presentation from JasperReports. Also with Aspose.Slides for Java (or for .NET) it’s possible to add new slides to the created presentations.
The only problem is how to add existing PDF files to a PowerPoint presentation. I see only 2 ways. 1. Create external predefined PPT files manually and add slides from them to a presentation using Aspose.Slides for Java/.NET. 2. Use some third-party tool and convert PDF pages to images. Later you can insert these images to presentation slides again with Aspose.Slides for Java/.NET.