How i can change logo disposition? And add image backgroung to blocks?

The best way would be to edit the css. There are two different ones defined, for the different colors:

style.css: This is for color specific styling. If you add a background that only works with the certain color, use this.
base.css: This is for non-specific color styling. Center the title using this.

In case you don't know css too well, find "#header img" in bass.css, and change it to the following:

#header img {
  //float: left;
  padding: 10px;
  //display: block; //you might need this, I'm not sure
  margin: auto; //you may have to do something else for IE, not sure if this will work
}

And to style.css, add something like this:

.sidebar .block {
  background: url("path to your file");
}