Embed File Within PDF

I already have both the PDF and the external file ready; what I need now is a clean, reliable way to bundle them together so the file lives inside the PDF itself. Please take my supplied PDF, insert the extra file as an embedded object, and return the finished PDF to me... (Budget: ₹600 - ₹1500 INR, Jobs: Adobe Acrobat, Editing, Electronic Forms, PDF, PHP)