Hi agarkitekter,
You can modify the single portfolio page in the theme files. Open includes>loop-portfolio-single.php and look for:
<div class="eight units alpha min_height_1 portfolio_container_image">
<?php if($slider->slidecount) echo $slider->display(); ?>
</div>
<div class="four units entry-content portfolio_container_content">
The classes "eight" and "four" are the grid sizes that the two sections should be out of the twelve column grid. So you could change it to nine and three or ten and two it just depends on what you want :)
Regards,
Devin