You really shouldnt be playing around with the Home directory, renaming or anything ...
BUT
All you have to do is create a new account, naming what you want where you want on the way, then copy the OLD home directory to the new Acct then delete the OLD Acct ONCE you have checked all is there in the New. Log out then back in and you should be right to go....
OH BACK UP BACK UP BACK UP just n case something happens
Cheers