AP,
I think you've got three main choices:
1 - Accommodation supplied by SFC (Someone previously suggested £70 per week)
2 - LMU Student Halls
http://www.londonmet.ac.uk/accommodation/
(Looking at around £80-£90 per week)
3 - Contact a london lettings agency (Probably looking at no less than £100 per week.)
CapCon