Hello Vitor,

I think you want to increase width for the box. But you are using responsive template and needs some changes in styles.css file. You can try to find it yourself. In Chrome and FF exist Firebug for it. But if you want me to change it send ftp access to my PM and I will change it for your site. Also what width do you want for the box. Right now it has width: 300px;

Also if you want to change it yourself go to ftp://templates>>your_template>>css>>style.css

find class at line ~1035: section#main_container > div > aside.left and change width from 300 to 340px
then find class at line ~ 5858: section#content and change width from 630 to 600px
then find class at line ~ 1178: section.side_block_search div.field.inline and change width from 90 to 110px save and check again.