BuddyPress.org

Hello everybody,
i am a newbie to wordpress and buddypress but i need to set up a custom styled website with the buddypress plugin. I have created a child theme based on the basic bp theme.
On the single view of a member i wanted to change the output of the posts. In the moment a post i displayed in the code like this:

<div class="activity-content">
<div class="activity-header">
<a title="admin" href="http://192.168.2.55/creativeworld/members/admin/">admin</a> wrote a new post, <a href="http://192.168.2.55/creativeworld/2012/04/bild/">bild!??????</a> <a title="View Discussion" class="view activity-time-since" href="http://192.168.2.55/creativeworld/2012/04/bild/"><span class="time-since">2 hours, 16 minutes ago</span></a>

</div>
<div class="activity-inner">
text mit bild

</div>
</div>

But what i want to have is a structure like this:

<div class="activity-content">
<div class="image"><img src="[featured image of the post]" /></div>
<h1>headline</h1>
<div class="text">Here comes the post text</div>
</div>

I have already build the structure like in the parent theme to change the output on this page down to /activity/entry.php but then i found out, that the html structure is generated somewhere in the core, is that correct?

So is there a possibility to change that?

Also i was wondering how i can get the userid of the member whose profile i am currently displaying!? If i had this i could write my own function to get the posts in the way i want them to be.

Thanks for your help
Tanzzwerg