Header Difficulites – Please help…

I am a beginner, so any help would be greatly appreciated.

I am trying to create my header in wordpress, so it matches my website design.

my website is http://www.classroom41.com
my blog address is http://www.classroom41.com/blog

I am having a problem once I try to put a table around my header everything moves.

Can you please help me? Thank you, Bryan