I'm the author of RedLine. Thank you for choosing the theme for your site.
As far as your questions:
1. Header image - If you don't want to use default image size 960x200, then you have to set the size you want (85px) in theme's functions.
In Admin panel > Appearance > Editor open Theme Functions (functions.php), at the top you'll see the parameters of custom_header function. Change argument
'height' => 200
with a value you desire (85), save the changes and you are done.
2. Date and time a.k.a infoarea :) - Again in Admin panel > Appearance > Editor open Header (header.php) find the following code
<section id="siteinfo"><div id="feedarea">
<dl><dt><span style="float:left;"><?php bloginfo( 'description' ) ?></span>
<?php echo date_i18n( __( 'l, j F Y - G:i', 'redline' ) ); ?></dt>
<!--End infoarea -->
It is placed after <body> tag, delete it (from Begin to End) save the changes and you are done.
Hope it helps :)