Friheten sleeper sofa pillow backs

Hi, I need to buy or make four new pillow back cushions for the Friheten sleeper sofa.  Can any one tell me if you can buy extra pillow backs from Ikea?  Or..can you buy fabric anywhere to match Ikea fabric on this sofa (brown or grey) anywhere so I could make them?  I prefer to just buy the pillow backs directly from Ikea or someone who makes them if possible rather than make them myself, but if I have to I will.  Anyone have any ideas on this?

Thanks so much for any advice!!