so I edit the CSS on "(view original stylesheet)"
No. You don't have to click on that link at all.
where do i paste the code I just changed?
In the textarea, where you originally pasted the whole CSS code, paste only this:
#wrap {
clear: both;
overflow: hidden;
padding: 0 15px;
width: 700px;
}
#header, #nav, #sidebar, #content {
margin: 0 auto;
width: 100%;
clear: both; float: none; overflow: hidden;
}
#header {height: 165px;}
#sidebar {width: 670px;}
.clearfix:after{
display: none;
}
That should widen your blog. Of course 700 pixels is a suggested value. You play with it till you find a width you like.
Also, make sure the "#sidebar" selector has 30px less than whatever you set your "#wrap" selector to. For example, if you set the width of your #wrap to 700, then the #sidebar width should be 670px; if #wrpa's with is 850px, then the #sidebar's width should be 820px.
You will have to set a new background image for your header as well since modifying the width of your theme will need you to modify the header image as well, otherwise it will look weird.
BTW, I won't be available till probably this weekend, so I hope these instructions were clear enough for you to follow.