The seat cover on my bike was knackered from being parked all day in the sun - went all stiff and inflexible. There's a trader on TradeMe selling replica bike seat covers for around NZ$70 - I bought one for my VFR after not being able to find vinyl that didn't look all shiny and cheap. It looks pretty much like the original - very well made, and good quality (non-shiny!) vinyl.
I didn't think I could use short staples in my pneumatic staplegun, and I couldn't hire an electric staplegun despite ALL the hire places advertising them, so I bought a $29 staplegun from Mitre 10. That did the job (it was the only one with a 'nozzle' that protruded so I could get staples into the awkward corners).

While I was at it, I stuck some extra 30mm foam on the top of the seat as extra padding so I sit slightly higher. (The reason is so that my legs are slightly less bent, and my head is sitting higher in the airstream over the windshield). I shaped it with an electric bread knife, and glued it on with spray-on adhesive before fitting the cover. Piece of piss!