alt123 there is only one terminal at HIA at the moment.

With regard to lounges have a look at the Wiki on the http://www.flyertalk.com/forum/qatar...unges-hia.html thread. Here you will see that there are two Business class lounges. However you will qualify for access to Al Mourjan lounge which, in spite of its faults, is one of the top lounges in the world.

Do have a look at the dashboard widget http://www.flyertalk.com/forum/qatar...h-airport.html which contains much useful information about your transit.