Hi
I live in London, do you know anything about Hackey at all? Have you been to London before? Hackney can be quite intimidating, it's quite run-down in some areas and have to say it's not the sort of place I'd want to stay on my own.
Just wanted to check you're fully aware of what you're getting into. You'd be hard pushed to find a nice B&B in Hackney so you might want to look further afield or places like Bromley or Bow. Closer to the city like Liverpool Street the transport links are very good but accommodation will be more expensive. This tube map will show you the nearby areas:
http://www.tfl.gov.uk/assets/downloads/standard-tube-map.pdf
Also it would be worth you looking at
Gumtree.com: UK's No. 1 in classifieds - jobs, property, cars and more as it has plenty of short-term rental accomodation and services.
Good luck and let me know if you need any further advice!
Heather