<Files *.*>
Order Deny,Allow
Deny from all
allow from "put your ip address here"
</Files>
then put your .htaccess in your admin or renamed admins folder if you have renamed it you will then be the only person that can login to your admins back end. (if your ip changes then change the ip address in the file or you will get page not found error)

Note you can still use this if you dont have a fixed ip address!! but you will have to change the ip address in this file when your ip changes.
regards