Alter Joomla header to allow our design and menu

We have a site that we are making which can be seen http://e a r t h.d n s1 [login to view URL]~h e a d l e y p/ Please remove spaces. The site is Jooma 1.5 with a purchased template. We want to remove the grass in the header and replace with whitespace so we can add a header image instead. We also want the suckerfish menu installed which we have or modify the menu to for more width, as if you see the menu is out of alignment Should be an easy task for a proper Joomla expert.