Greetings!
Have you tried asking your neighbor for their password? If it is protected, it probably means they don't want anyone else using the service, which is fair and their right as they are paying for it. Maybe I am totally misreading the situation here, and maybe you can clarify if I have it wrong, but if you are looking for help to basically hack into another person's system, you won't find help for that on this forum. Again, if I have misread your question and there is a legitimate situation here, please clarify so that we can help, but your above question sounds like you are just wanting to be able to use your neighbor's wifi even though it may be protected...