You may be able to get an individual grant from local charities see Ins and outs of choosing a car.
Social services may be able to help you with costs if you do not get DLA. Or if you are in or applying for a job, try the Access to Work scheme. Contact your local Jobcentre for information or visit:
Wigan Jobcentre Plus
71 King Street
Tel: 01942 752 100
Tel: 0845 604 3719
Transport for Greater Manchester