It is very simple. First, get her medical done immediately. The results come in within three days. If she clears the medical test, just go to any passport and immigration office with her passport and your ID card, pay the fee of QR 200 per each month of extension you want through ATM card, and they will extend the visa. You could visit the immigration office at Messeimar. Try avoiding the one at Madinat Khalifa as there is usually a very big rush there.