Pmode is a 2 column fixed width wordpress theme.
You have an option to change header image which is present in the image folder of the theme. Choose the image of your choice and name it as image_bar.jpg. place it in the image folder in the theme folder named pmode. The image size should be equal to 900*166px.
Inserting a link block in the sidebar is simple too. Just enclose the title of link block in <h1> and </h1> . use a simple unordered list without and css tags. Place a divider div block which is used to divide 2 link blocks in sidebar after unordered list to complete the insert.
Let me know if you face any other problem.