Hi, I try to answer for as many questions as I know.
Q1. I suppose you need to open the footer.php or header.tpl file to add the adsense code to the suitable spot.
Q2. The logo image seems to be controlled by the css file
Code:
#logodesc {
background: url("images/header.jpg");
height: 191px;
}
If I were you I wouldn't touch the css, but copy a square part of the header.jpg which contains the GTA text and would put it into the header template file like this
Code:
<div id="wrapheader">
<div id="logodesc"><a href="http://gtagamers.net/"><img src="sliced-logo.jpg" style="float:left"></a>
<div class="member"
It will create a link to your hompage as well.
Q3. Have a look into the admin control panel
Q4. I'm sure that you will find this setting at the admin panel.
Good luck!