A consultant in XMPP / messaging/ state update / presense

We have a product that consists of a desktop client (at student side), and a web application in Django (instructor side). We have few features that are messaging type or status type. For example, we need the following:
- to have a direct chat between student and instructor
- broadcast message from instructor to all students
- If the student is online or offline (close the application)
- And some other status updates

We are currently working in polling mode. Each clients sends a request message to the server every 4 seconds and gets the available information about these details from database. This of course causes the database to be overloaded. We would like to redesign this part. We want a consultant to help us in choosing the correct technology or service after understanding our system
We need someone that have done this before to give us consultation
We need 3 hours meeting to explain our system and discuss what are the correct technologies and the starting points to implement them