Title Header Problems… help!

I am brand new to wordpress so my apologies for my lack of any basic knowlege or terminology..

I just used this handy link to put an image in my title space at the top of my page.

However now the only problem is that there is too much space on top and the bottom of my logo. How can I decrease this margin on the black area? I am not very good at programming so hopefully there is a relatively simple way.

Thanks!