Here's a list of agents from the Yearbook in case you can't get a copy - should be in your local library -
http://www.writersservices.com/agent/uk/index1 .htm
Suggest you do not self publish - especially if you want to get the book into the shops, which would happen if the content is of interest to a publisher anyway.
You will have to find a publisher - if you don't go the agent route - that is interested in the topic of autobiogs., and expect a lot of rejection slips which is par for the course in getting a book to the reader.
You will need to submit a synopsis of the contents - double spaced is best - and an SAE if you want the MS returned. Not all publishers not agents return what is sent as they receive too many to be viable. Expect to have some sort of reply at the least to say thanks but no - if one doesn't come back to you don't watse your time chasing as they would have contacted if of interest.
There are a a lot of resources on the net about publishing your bbok, but start by finding either the aganet that can give you honest critiscm, or a publisher that can handle a niche title - be prepared for negartive comments too, by the way - not being nasty but your friends will always say it is a good read - you need to get that from a commercial/dispassionate source to see if it is true.
Don't be put off by any rejections though and take the comments on board, and if you are serious, you will achieve your aim. Good luck!