I bought a 'band expander' off t'internet some time ago for my japaneese car radio.
It has a switch which increaces the frequency by +10 or +20.
Seems to work reasonably well.
From
http://www.japaneseimports.co.uk/faq.htm
Does the radio work?
Normally no - but we can fix it before you get the car with a clever device we get from New Zealand (where the imported cars have been going for years). It takes a short while to fit, and although the radio display won't be accurate, you can get nearly all the UK stations. Just use the presets, and the jobs done for you. These are top quality units which you can purchase for a nominal fee.