wider post fields and thicker font on menu bars

I need some help to change the following items on my website, I hope you can help me : 1: I would like my post fields to become wider, how and where can change this ? 2: When I press one of my posts, then the heading I been seen twice just below each other. I need this to be changed so it only shows once, how can I change this ? 3: My Side and category menu bar, I would like to make the font thicker, how can I do that ? My homepage is: http://garnmasken.dk Best regards from Anne-Pia Hansen annepia13@gmail.com