Urchin hasn't been updated since 2012.
If you're ready to replace Urchin,
Check out Angelfish Software

Urchin Support Plans

Urchin 6 Co-Branding

Adding a custom header to the top of each Urchin 6 page

Rename each file in path/to/urchin/lib/custom/cobrands to end in .tpl. Each of these files represents a different part of the Urchin interface. If you open any file, you will see where to add your HTML to display. To create a consistent header across all parts of Urchin, copy the HTML you write into each of the three files.

For more advanced co-branding, such as changing colors or creating custom interfaces, contact Actual Metrics.