How to extend the horizontal line and colored box all the way?

Question

1. I want to extend the horizontal line and the colored box all the way to the end of the page, however using \hrulefill (instead of \hline, screws up the format.)

   This is my code: http://pastebin.com/Xd1jWqBb and this is what it looks like:

2. Also, how do i reduce the gap between the colorbox and the start of the text within it?

3. If I were to use Answer 2 (located in my code) i get this:

however the heading should be shifted towards the left. If I do that, how do i extend the color and the line all the way to the end.

So ultimately i want

but with the colorbox extended as well.

I posted a similar question and the above problems are the by products of the answers given from the other post. (Ref: How to edit the length of a color box?)

Answer 1

For such a color box problem I would recommend a color box package like mdframed or tcolorbox.

A tcolorbox solution would be:

\usepackage{tcolorbox}%  preamble AFTER \usepackage[usenames,dvipsnames]{color} 

...

\newcommand{\headergrey}[1]{%
  \begin{tcolorbox}[enlarge left by=-15pt,width=\linewidth+15pt,
    arc=0pt,toprule=0pt,bottomrule=0.4pt,leftrule=0pt,rightrule=0pt,
    boxsep=0pt,left=6pt,right=6pt,bottom=4pt,top=4pt,
    colback=black!10!white,fontupper=\scshape,
    after=\par\nobreak]#1\end{tcolorbox}}%

\headergrey{Objective}
Seeking a Full Time position in the area of balh blah blah blah.
\vspace*{6pt}

\headergrey{Education}
\school {University of Latex}{Latex U.S.A.}{May 2013}{Masters of Science in Latex}{Adviser: }{GPA: xxxx}

This gives the following result (with your output in comparison):

You can shift OBJECTIVE by adjusting the left=6pt option value.