I can't help wondering about what type of accommodation requires a rental of twice the minimum wage. The take home pay for someone on the NMW, working a 40 hour week, is around £197. Rent of nearly £400 per week seems ridiculous for what is presumably fairly basic accommodation!
Shelter can give advice on matters specifically related to housing. Call 0808 800 4444 (0800-2000 weekdays, 0800-1700 weekends).
Your local CAB give advice about tax credits, benefits, etc. Find them from here:
http://www.citizensadvice.org.uk/cabdir.ihtml
Chris