As of April 21 2015, Google will be changing it's ranking algorithm to include mobile friendliness as a factor. This means that your ranking will drop for searches done on mobile devices, if you're website is not mobile friendly. We won't know the true impact of this until after April 21 but I would suggest that you start thinking about updating your website now to a responsive design.
Here is a link to Google's official statement.
For costs and details of getting a responsive website please see our Small Business Website Design page.
If you have any questions please don't hesitate to contact us.