When your logged in as the admin to your site, you can go to the Marketplace and install the modules/skins you've purchased by clicking the install button.
If you are using the FireFox browser, you should get the developer tool or Firebug add-on, then you can right click on a link or any element of your page to find the CSS class its using.
The link color your wanting to change is in the core_html.css file.
I'll take a look, it may take me a while as I'm just going to go through all the css files for Nova and make sure that what can be modified gets added to the styles tab.