Which court did you attend and what was the amount involved? If you attended an English Civil Court they should have outlined your options to have the judgement enforced.
Basically, once you've got a judgement you've got to find the defender and make him pay. The defender has to explain why he can't pay the sum and fines awarded by the court.
You need a solicitor to enforce the judgement. Any solicitor who specialises in civil matters should be able to deal with this case.