Is there any way I can monitor how much data transfer my site is utilising?
Yes, within your Mission Control panel there is a tool that will allow you to view how much inbound and outbound traffic your web site is incurring on a monthly basis. All you need to do to view this information is to log into your Mission Control panel with your username (VS Number) and password, and click the ‘Web Server’ then ‘Traffic Usage Meter’ links from the main menu.