Replace Logo-image with text

you can do that by subtext option – this inserts f.e. the bloginfo name and description as text.
– but you do not need to insert these dynamic texts – you can insert simple html too
( this inside child-theme functions.php)

add_filter('avf_logo_subtext', 'kriesi_logo_addition');
function kriesi_logo_addition($sub)
{
  $sub .= "<h1 class='logo-title'>";
  $sub .= get_bloginfo( 'name', 'display' );
  $sub .= "</h1>";
  $sub .= "<h2 class='logo-title logo-subtitle'>";
  $sub .= get_bloginfo( 'description', 'display' );
  $sub .= "</h2>";
  return $sub;
}

then you can set logo img to display none – and style the text via quick css too ( positioning; font-size; colors etc. )
btw: : you can see that here on top with logo and text. this “kriesi.at” and “Premium Themes” is placed that way ( but only in strong tags)

PS: you can insert this way dynamically the page title as second text by replacing in the code above

$sub .= get_the_title();

f.e.:

#top .logo img {
  display: none
}
#top .logo,
#top .logo a {
  overflow:visible
}
#top .logo-title {
  font-size:12px;
  color:#000;
  position:absolute;
  left:0px;
  top:-7px;
  white-space:nowrap
}
#top .logo-subtitle {
  color:#aaa;
  top:7px
}