Changing Blogs URL

I changed my wordpress blogs URL from
/wordpress
to
/wordpress/index.php
And this happened:
http://67.15.28.10/~agatio/wordpress/index.php
It appears the template has been messed up.
But I can’t edit it as when I try to access the admin CP, I get a 404.
Twice this has happened, it’s easy enough to delete it off the server then re-upload, but is there any way to fix this?

EDIT: I see what I have done. I changed the URL which changed it for imagea etc. making the theme stylesheet void, and the links to the admin CP void. Is there any way to get into the admin CP after doing this?