You appear to be now using twenty thirteen instead so I've marked this thread as resolved.
Just for your general information though...
Featured image sizes are set at image upload time.
So if you want a smaller image you need to change the size in Settings > Media and use regenerate thumbnails plugin by viperbond007 to resize any existing images (or just upload new ones).
Theres a switch in the Pro version of the theme to float the images left like on my demo site http://creativitypro.com.
If you wanted to do it manually by adding a float:left; if you look in the css for the styles related to featured image. Probably a margin-right: 15px would be useful too.