BuddyPress.org

Hi
I have just installed buddypress and as am new to this, i seem to find this a problem to increase the height of the header. I have a custom header image and the height is more than 125px. I followed a tutorial on how to do this. Heres the link: http://buddydress.com/2010/04/custom-header-tutorial-adding-an-image-and-changing-the-size/
According to this i need to go to function.php at line 149. I looked there and painfully everywhere there and could not find the place indicated. I thought maybe its a version issue. So, i went to the default.css and did the editing there.
When I came back to the backend and went to the custom header i was asked to crop exactly 1250×125 which means that the edit i did at the default.css has only changed the height on the front page but not at the theme header.
Have a look at the site http://www.weightlost4teens.com and you will see what i mean.
Basically, i need to get to the php file (if function.php is not the right one) and increase the height there.
Please help and thanks a lot!