I have a Joomla site that I need to update to mobile friendly in preparation for Google's new algorithm. What is really important to me right now is updating my dynamic item page (I sell a couple hundred products) that adapts to whatever product. Since these item pages represent about 99% of my webpage, is there a way to just update that to mobile friendly for now? I don't know how I would do it since I am using an old RocketTheme template that is not responsive.
You can contact Rocket Theme support for responsive version of the theme(If they have one). Or you should hire a developer and a designer to convert your existing theme to responsive.
The Joomla 3.x comes with responsive theme by-default. If you are using Joomla 3.x. Try to switch to default template and check if switching template and then apply your current theme changes is shortest development path or directly work on Rocket theme changes are.
RocketTheme do a wonderful job updating their older templates to work on newer versions of Joomla. Check the compatibility matrix for which templates are responsive:
If you have an older RocketTheme template with no responsive option, I recommend choosing a newer responsive RocketTheme template and customising the CSS along the lines of the previous template.
Assuming your current template isn't too old, the module position names may still work without any changes.