I believe what you are looking for is in header.tpl...
Code:
<td><table id="topnavbar">
...links here such as Support, Client Area, Announcements, Knowledgebase, Support Tickets, Downloads...
</table></td>
Also, under that is an area with links to show if logged in...
Code:
{if $loggedin}
...links here such as My Details, My Hosting Packages, My Domains, My Invoices, My Support Tickets, Order Additional Items, My Products & Services, My Emails, Logout...
{/if}
If you want to change the icons on the main support page, that's in homepage.tpl