There is no way to determine the maximum number of visitors your site can sustain. Each site is different and the amount of traffic you can handle will depend on the resources each visitor is using.
Once you are online, you can view your site statistics, like the number of visitors and which browser they use. Your cPanel includes a statistics program called AWStats.
If I need to handle more traffic, what should I do?
My best recommendation is to request to have your site bandwidth and quota via sales@gomedia.com.au.
For more traffic still, you can contact sales@gomedia.com.au to make special arrangements to meet your specific needs.