That theme does not have a set width — it’s “responsive” to change width according to the browser window or device size. So you’d probably have to do quite a bit of modifications to change that — changes would be made in the CSS styles.
For more help, try asking on the StudioPress forums — as support is included in your theme purchase — and commercial themes are not supported here.
http://www.studiopress.com/support/
If you need to change the max width of your blog, There is a class called .wrap {
margin:0 auto;
max-width:1140px;
}
change this to the size you want “max-width:1000px;”
you may need to create support ticket for it or if you have a little bit design skill, you can set it from style.css otherwise you should hire any developer for it.
