Retrofitting App to use CodeIgniter

[eluser]Crafter[/eluser]
I used apache's htaccess

Code:

# If the file or directory exists, show it
    RewriteCond %{REQUEST_FILENAME} -f [OR]
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteRule ^(.+) - [PT,L]

    # Blank queries get sent to the index
    RewriteRule ^$ /index.php [L]

    # All other queries get sent to the index as index.php/whatever
    RewriteRule ^(.*)$ /index.php/$1 [L]

In this way i had a directory stucture
application --> CI's directory
admin --> old app
somefile.php --> oldapp