There are plenty of free responsive WordPress themes, enough to find one that suits your tastes.
Why run 2 separate sites for your business, a PC and mobile version, rather just switch to using a responsive theme which will adapt on the fly to the device that is being used to view your site. Obviously you have to tweak what displays and what gets dropped as the screen size shrinks.
Responsive WordPress Themes
Themeshaker has a nice selection of free responsive themes. Click Shake it and select Free & Responsive and any other criteria you need.
Buttercream – Download or install directly from within WordPress by searching for Buttercream under Appearance/Themes then Install Themes
Testing your Responsive Design
Here are a couple of great tools to view your site in a couple of common sizes to see how it responds.