Navigation Bar Problems

Hi!
I've a BIG problem with the NavBar of the forum I'm the admin of. (www.projectw13.newstarforum.com)

Slowly, this d*** thing is driving me crazy. I'd like to have a NavBar below the header image, but if you take a look at the forum you'll see that the bar is covering that image. Before I got it this far (beats me how I did it - I'm completely new to CSS) the images for the bar were all of different sizes (one tall, another looked like being inside a trash compactor, a.s.o.).

So, my basic questions are:
1. How do I get this bar below the header image?
2. How do I manage that the images are keeping the sizes I made them with (with Photoshop CS4)?

Thank you for your help!

Hello? Anyone any ideas of how to fix my prob?

Thanks for NOT helping me! Close this thread and forget it!