Hey, you need to be very careful ! Business visa is for 3 months yes. When you enter Qatar, you get only 1 month stay. At the expiry of 1 month, you need to renew it further for 2 more months at a time or separately for 1, 1 month. There are 2 ways to renew it, 1st, manual way in which Form needs to be filled, signed ans stamped by your sponsor company attaching your visa copy with it. At immigration they will renew it. The 2nd method is very easy through self help machines in immigration offices, the PRO of your sponsor company needs to go to immigration with his PRO card + company mudeer card( authorized person in company) + ATM card, with few clicks, it will be renewed.

Please note, as per my knowledge, there is fine of QAR200/- per day if you do not renew the visa. Hope you are saved from it but immediately start chasing your PRO and sit on his neck until he renews it. Cheers!