Help with website editing

We are a executive Search recruitment firm who require some editing of our website. This will include replacing the existing pie charts with new ones and ensuring that the labels, fonts and positioning is all the same. (3 pie charts, currently sat in powerpoint). We also require a new link inserted from the home page, listed underneath the exsiting links to be called Interim Management, a new division we are launching in January, hence the urgency of this project. We will provide the content for this, in Word. Our concern is that the website was designed over 5 years ago, and editing historically has been through the software called Macromedia Contribute 2, which we believe is an out-of-date version (version 2.1, 2003). Recently editing has proved difficult with corrupted results, particularly with the pie charts. The website address is : www.harlingmenzies.com.
We are a small business with no dedicated IT Manager and therefore require a specialist help.