How do I access Itunes U Course Manager if my country isn’t supported?
Use a VPN.

You can use a service like TunnelBear (not affiliated) so that you can appear to be using the service from another country.  

If you have a "friend" in the country of question, you can set up your own VPN (OpenVPN) between your and their locations.  This is obviously a DIY solution and you would need the requisite skills.