“maintenance records showing that all regular maintenance was completed on time”
This statement is apparently not true. Unless the timing belt was, in fact, changed back in '09 sometime. If it was changed back in '09 according to the regular maintenance schedule, then that resets the clock. If, as I suspect, it was not changed then you are about 3 years overdue. It says 7 years. Why would that be put in there if you were just supposed to ignore it?
As Docnick said, budget something in the neighborhood $700-900.