Do you own both of those cars outright or are there finance agreements in place? Changing to cheaper cars might make sense. (I'd never pay more than about �300 for a car. They might not be particularly stylish but they get me from A to B).
What do you mean by 'a bit more sensible with the food shopping'? Try fixing a definite budget and sticking to it. (I reckon that �10 per week per person is 'tight but feasible'. �15 per week per person is 'reasonable'. �20 per person per week is 'generous'. Despite that, I still know people who seem to spend �70 to �100 per person per week and who don't seem to eating any better than those who spend far less).
If you really can't find the necessary savings, and you've got a mortgage, youmight have to consider asking the lender to extend the period of the loan, thus reducing the monthly payments. (That's quite a big step because, in the long term you'll pay far more. However, it would still be better to do this now than to be hounded, by the lender, for non-payment of your mortgage later).
Chris