I have "resized" the left portion of my address bar by taking the address bar image into Photoshop, enlarging the canvas x amount of pixels to the left (the same amount I want it to 'shrink' down by), then changing the left sizing margin appropriately (making sure sure to add the added width on top of the current left pixel allocation -- so for instance, if sizing margin had values of 3,3,3,3 and I added 10 pixels to the left of the image, I would now change it to
13,3,3,3). Finally, I would change the content margins appropriately by adding the same added width (10 pixels in my example) to the left content margin.
Perhaps you can try the same on the Search box section.