Helo friend u need to go to Gharaffa main immigration office(early morning so that time not much rush) and required documents are following..

1.U should hve a salary QR 4500/-5000/- for applaying Visit Visa for ur wife/relative.
2.NOC from the sponser(arabic)staring ur position(u shouldn't hold a labourer category)
3.A proof of relationship such as marriage certificate/birth certificate attested by foreign affairs.
4.Labour contract,passport copies,ID copy of the sponser.
5.Two Photograph and passport copy of the visitor.
6.The Charges are 200QR/person for each month.
7.RP copy of the sponsor.
8.Rental agreement copy(they may not ask it everytime but it act as a supportive document)

Best of Luck...