How to purchase IRIS?

Hello there, 

I am Zainab a Medical Practitioner for a leading hospital in India. 

But i am about to start my new clinic and gradually build it to a hospital as well. 

I already have a very strong patient Data Base but I am afraid that day by day as it is increasing i will need a better one to handle things. 

I have a considerable amount of knowledge in IT as well. that is when I came across this thing called IRIS. 

I also saw we can use it for free. 

I need more details please on this. 

I also see many versions of IRIS. Please clarify that for me as well please. 

Hope someone can help me please. 

Thank you.