Changing post details

I need some help. Im using this theme atm http://wordpress.org/extend/themes/pyrmont-v2
And i want to change these details
http://www.kabington.com/change.png

Get rid of the date in the orange box and Change “Category: Uncategorized / Tags: no tag / Add Comment / Edit” to “Posted on August 28th, 2009 by Firstname Lastname”

Can anyone tell me the how to do this.. Looked at the CSS script but i feel i need to be looking at one of the many PHP scripts.