Most support people don’t look at the newest tickets, so bumping doesn’t help.
You appear to have the Firebug add-on for Firefox. You can inspect elements to see what the HTML code looks like, as well as what CSS is being apply to elements of the theme. If you right-click on your sidebar and click Inspect Element, it will pop-open a window and have some element selected. Look for a parent element of that selected item that is a div tag. If you hover over the div tag it will select the entire sidebar in your browser. Click on that div tag and look at the CSS that is being applied. It will list the styles from most important to least important. Look for one property called width, then go change that value in your theme. If your do it in Firebug it will show you the change temperately, so you will have to use FTP or WordPress editor to change it for real.
For the TwentyTen Theme the CSS in Firebug will look like this:
#primary, #secondary { style.css (line 71)
float:right;
overflow:hidden;
width:220px;
}