Hello!
I would add one more class into your code:
<div class="top_top"><div id="left">
<div id="txt_left">
<h2>A</h2>
</div>
<ul id="navigation">
<li><a href="reg.html">1</a></li>
<li><a href="konto.html">2</a></li>
<li><a href="profil.html">3</a></li>
<li><a href="layout.html">4</a></li>
<li><a href="mit.html">5</a></li>
<li><a href="benach.html">6</a></li>
<li><a href="entw.html">7</a></li>
</ul>
<div id="txt_left">
<h2>B</h2>
</div>
<ul id="navigation">
<li><a href="impressum.html">1</a></li>
<li><a href="impressum.html">2</a></li>
<li><a href="impressum.html">3</a></li>
<li><a href="impressum.html">4</a></li>
<li><a href="impressum.html">5</a></li>
</ul>
<div id="txt_left">
<h2>C</h2>
</div>
<ul id="navigation">
<li><a href="impressum.html">1</a></li>
<li><a href="impressum.html">2</a></li>
<li><a href="impressum.html">3</a></li>
<li><a href="impressum.html">4</a></li>
<li><a href="impressum.html">5</a></li>
<li><a href="impressum.html">6</a></li>
</ul>
</div></div>
and then add this into your css:
.top_top
{
position: absolute;
top: 0;
}
Now to make the navigation go to the top right, again one more class:
<div class="top_buttons"><div id="header">
<div id="navigation_top">
<a href="index.html">Einführung</a>
<a href="impressum.html">Impressum</a>
<a href="http://www.google.de">Google</a>
</div>
</div></div>
and put this anywhere in your css:
.top_buttons
{
position: absolute;
top: 0;
right: 0;
}