I would suggest that you contact the creators of Easy Profile Pro and ask them if they are able to create similar functionality as provided in the products that you mention. They may be in the best position, as it is likely their code will need to be modified, if you decide to pay someone to write the code to provide the functionality.
I need to add the function to view the visitors of my profile.
It is not clear from that statement whether you want to be able to display to registered users looking at other users profiles like in the Social extensions that you mention or if you're meaning who is viewing just your profile. Or are you wanting to record who is visiting your site and looking at your profile page which is something different again.
If you want more specific help you will need to expand your question to provide more detail about what problem you are trying to solve.
A look through the JED shows a couple of add-on extensions that provide that capability in the Social extensions that you could contact and ask their authors if they could be adapted/copied to work with Easy Profile. Otherwise you need to look for alternative profile manager extensions for one that has the capability or feature that you want, however I didn't see one.
Although your requirement might seem simple, 'Display who looked at my profile', the basics steps to achieve that in programming regardless of the existing extension(s) that you have would be.
Find the piece(s) of code used to display a profile, intercept that code to capture the details of the user that is viewing the profile. If they are just a visitor, not logged in, to your site you might not get much more information that their IP address and the browser they used.
You need to build somewhere to store the details of the the profile viewed and who viewed it. This would probably be a new table in the Joomla data base with programming code to save the details and retrieve the details and some way to manage(read delete older records) the details in the table which might be more programming of an interface in the Admin section of your site.
And finally to display the details you have saved in the database, you need to code how you want them displayed, where you want them displayed(front end, back end, in Easy Profile) and what details you want displayed.