Hi, The minimum salary for Family Residence visa is 10,000/= QAR. So you are eligble to apply for family residence visa.
Reqirements:
1- Printed application (from any typing centre)
2- Supporting documents

Wife passport copy+marriage certificate
Baby passport copy+Birth certificate (MARRIAGE & BIRTH CERTIFICATE should attested from QATAR EMBASSY in the issuing country and MOFA in QATAR)
Your (Contract with the company) copy
Your QID copy
6 months bank statement
Tenancy aggrement copy
Degree copy

Along these documents you need to go to MOI AL Gharaffa (main immigration) Gate no. 3 and submit these documents.