Create Wedding Portrait from Separate Photos

I have wedding shots of my mum and dad standing with other guests. They never posed together on the day, so I need one convincing portrait that shows them side-by-side as if the photo had actually been taken at the event... (Budget: £10 - £20 GBP, Jobs: Digital Art, Graphic Design, Image Processing, Image Recognition, Photo Compositing, Photo Editing, Photoshop, Photoshop Design)