for the logo, edit the webassist/themes/Purple/css/purple_styles.css file:
padding: 30px 0 0;
I'm not quite sure what you mean by:
b.) I also want to modify the space in between the pods.
Please prove some more specific details.
changing the layout of the pods for a specific design will not be an easy task, you would be better off using the default layout that has the pods placed the way you want them, then using the design editor to change the look of the design to use the colors from the purple layout.