From the last information I have you must have the medical done and the visa extended within one month. I do not know if there has been a change to this rule. Also, the extension to the visa could be done at any of the several passport & immigration offices located in Doha and you need not go to the one located in Madinat Khalifa as there is usually a heavy rush there.

But just to be sure, suggest you wait three days if possible to allow for other QLers to reply to your query.