how to decrease the empty space left and right of page

what is your screen resolution?

consider what most of your users will see:
http://browsersize.googlelabs.com/

changing the overall width of a theme needs editing style.css and adpating quite a few of the styles – and requires quite a good knowledge of css.

possibly try to use a tool such as Firebug to identify the involved css selectors; http://getfirebug.com/

helping with pure formatting problems is not really within the main scope of this forum.

I actually made my page width bigger using the following method.

I edited the images in the wp-Creativix/images directory and made them all 100 pixels wider.

These are the png files center-column,sub-top etc.

Copy the images folder to your PC, then create wide version of these files in a separate directory. You will have to copy them back after a them update.

You also need to edit style.php in the wp-Creativix directory.

Again I saved this in anotehr directory to copy back after an update.

The changes are mostly adding 100 to the width parameter for different components. There are quite a lot of them.

eg change

#wrapper {
width:925px;
margin:0 auto;
}

to

#wrapper {
width:1025px;
margin:0 auto;
}

I can send you the files if you like.