Show the author in a new post

Hi,

I have 5 users in a wordpress installation. When a new user writes a new post, we get the following:

Hello world!
Published July 9, 2008 Uncategorized 1 Comment Edit

I would like the author of the post to be shown, i.e.

Hello world!
Published by author_name, July 9, 2008 Uncategorized 1 Comment Edit

I cannot find the option to show the author in the Settings panel, and I do not have access to the source code, therefore I cannot modify the php file. I cannot install any plugins.

Is there any way to show the author? Thanks!