Thanks Daniel!
Just before receiving your reply I found a solution for this changing line 657 In my JA_purity template.css
I made the "a.readon{}" float right instead of left and it´s working.
Although this is not exactly what I want it´s working and will give me more time to look into the topic that you pointed to me.
Here is the code that i changed. Maybe this will help someone.
a.readon {
float: right;
margin-top: 10px;
padding: 1px 5px 1px 14px;
border: 1px solid #F6F6F6;
display: block;
background: url(../images/arrow.png) no-repeat 5px 48%;
color: #006699;
font-weight: bold;
text-decoration: none;
text-transform: uppercase;
}