There are several PDF generation engines available as open source. Completing this project would involve utilizing one of these engines for PDF generation, and possibly for the printing requirement also. I would then convert the Excel template you have into code, and combine that with the existing PDF to create the final PDF.
If, however the Excel template might change in the future, I could have the application interpret the template construction, and then convert this information into code. This would take some extra work. I am not aware of a simple method for bringing an Excel template into a PDF document without having Adobe Acrobat (the full, not free, version) installed on the computer that will be using this application.
Also, if you would like to populate any of the template fields with data, this could be arranged.