Probably by now you could have solved your problem.
Normally these iphones are supplied through a service provider and registered with them.Especially iphones (Smart phones) do not work if purchased in one country and are to be used in another country. But there are so many shops in Doha who unlock them.

Getting Wifi should not be a problem as it is similar to a Lap top as long as the settings are right.
However if you still have a problem there is a site where in you can get the answers and also there is a live chat. They would take step by step to activate your phone.

http://www.fixya.com/support/t3229114-gprs_not_working_not_working_samsung

try this URL. There are also some queries similar to yours but the answers tto that is unfortunately another Unlocking URL in which they charge. Don't try that, it is preferable to get it unlocked at Doha wherein atleast you can contact the shop again if you have any further problems or for any queries.