sSince your baby is over 3 months,Go to labor department and get the sponsering family application and then do the following:

1- FIll it up at any typewritter
2- make a copy of your passport and ur wife's and child include the RP page as well for both parents.
3- NOC letter from ur company
4- your contract
5- copy of Electricity&water bill.
6- unabridged birth certificate of your child translated to Arabic and attested.

Submit all the above back to the labor depatment and then wait for the approval in 3 days time.

Then you can go to the immigration department and request to print your visa and pay the fees 200.

GoodLuck.