As far as I know, there are some requirements to be presented and completed to be able to get family visa like:
1. company letter stating your profession, basic salary,housing allowance, food allowance
2. NOC from your company
3. copy of your contract, marriage certificate, passport both of you, diploma and qatar ID
4. salary certificate and 6 months bank statement

Complete all these requirements before you will go to the immigration. But take note that you cannot get family visa if your salary does not meet the salary bracket required by the immigration, I don't know how much now is the allowable salary.
Goodluck.. Hope you can get visa for your wife.