You might be able to get hold of a steam cleaner from someone you know - my Mum sometimes has one floating about which I used on my first car when I got rid of it (it had biege seats which obviously marked fairly easily).
Steam cleaners will remove virtually anything.
I think Argos or somewhere like that might sell the steam-cleaner thingys for the home; worth a look (buy the missus a pressie "to help ease the burden of housework"
)
I can vouch for the Gunk stuff - use it on my bike marvellous stuff.... Hexus review anyone
?