Cannot Resize Header To Fit Larger Logo

OOPS! I forgot to leave link to the site I am working on so you'll have an idea:

http://myamericanfurnituregalleries.com/

Hello,

I have replaced the NopCommerce logo with my own. However, I can't seem to make the Logo display any larger in the Header. The original Width & Height of NopCommerce's logo was 340 X 70 where mine is 294 X 89. There are 2 places I can find the settings for the Logo; I can find it in BOTH master.css files; one in "App_Themes\administration" and another is in "App_Themes\darkOrange" directories.

I changed the settings of master.css file in "App_Themes\administration" as follow:

ORIGINAL SETTING:

.header .logo
{
  background: url('images/white_afg_logo.jpg');
  display: block;
  width: 217px;
  height: 67px;
  text-decoration: none;  
}

UPDATED SETTING:

.header .logo
{
  background: url('images/white_afg_logo.jpg');
  display: block;
  width: 294px;
  height: 89px;
  text-decoration: none;  
}

The result however had no effect.

Secondly, I changed the settings of master.css file in "App_Themes\darkOrange" as follow:

ORIGINAL SETTING:

a.logo
{
  background: url('images/logo.gif');
  display: block;
  width: 225px;
  height: 60px;
  text-decoration: none;
}

UPDATED SETTING:

a.logo
{
  background: url('images/white_afg_logo.jpg');
  display: block;
  width: 294px;
  height: 89px;
  text-decoration: none;
}

The result however had no effect.

Anyone with a solution or have encountered this before, your feedback is appreciated. OR... could this be a bug in NopCommerce? I am using Version 1.0

Many thanks!

I have replied you here: https://www.nopcommerce.com/boards/t/5386/how-to-replace-header-logo-with-my-own.aspx