Hello Evelyn,
You will have a devil of a job getting hold of an instruction book for that model if you are in the UK, the only possibility is to try tandtrepair.com this is a major Singer supplier of books and spare parts mainly in the US or you may be very lucky as a first try if you type in Kenmore sewing machines, scroll down to Relics and you will find the 507 book available from the US.
Ken
Ken Dourof
May 2007