Lots of good information everyone, so to summarize

i) Upgrade your routers firmware to the latest version

ii) Use the highest router security settings encryption your clients will support.

iii) Use a long password using random character string preferably more than 256 bits i.e. > 16 characters

iv) Create a MAC address filtering list.

v) Ensure your router password is just as strong.

vi) The SAS wannabe thunderflash bang throwing Walter SWAT team may still turn up at your front door before kicking it in. Counter terrorism/police stupidity is sometimes difficult to counter act or prepare for.

http://www.youtube.com/watch?v=62OmbAWC08o