open your stylesmilky_waytemplate
overall_header.html
find
<td height="150" align="left" valign="middle"><a href="{U_INDEX}">{SITE_LOGO_IMG}</a></td>
and replace with
<td width="200" height="150" align="left" valign="middle"><a href="{U_INDEX}">{SITE_LOGO_IMG}</a></td>
so here you can try chage it width="200" height="150"
if you need more than 150 of height you will need also to cgane it in
stylesmilky_waytheme
stylesheet.css
here
#top_logo{
border-width: 0px 0px 0px 0px;
margin: 0px 0px 0px 0px;
padding: 0px 0px 0px 0px;
background: url('./images/top_header.png') repeat;
height: 150px;
}