Why not just use the set_title('My Title') method and incorporate the title into the bar graph?
Update: When you make a change to your original node, please annotate it as such, using a bold Update tag. Additionally, I notice that you are creating your graph using data from arrays @xaxiss and @yaxiss, yet those are previously undeclared. Where is your graph data coming from? Why aren't you using strict? You might want to consider backing up and using sample code from the synopsis section of GD::Graph. Get that working, and then modify it one attribute at a time until you have what you want.