Paragrams theme posts issue

Hi there,

here is a link to a single post on my site.

http://www.nicshonfeld.com/tagebuch/?p=460

As you can see there is an issue with the width of the post being far too narrow. i cant for the life of me work out how to ammend this so it (i need it 700px wide to accommodate my content). It seems to be better with Chrome and Internet Explorer but still needs to be set wider.

any ideas??

thanks in advance.