Family visa apply.

I, taufique got job in oman . My total salary is 600 Omani riyal. i am having labor visa. i want family visa for wife and two children. Is it possible ?
If possible then how much i have to pay? What is the procedure.

Now i am asking my family to come on visit visa but that can be extendable up to 4 months only. That becomes costly for every time.

Please let me know urgently...... :(

Your visa has to be eligible for apply family visa. Please check with PRO whether your visa category is eligible for family joining

Thanks for the information bt how to check with PRO? what is the procedure and PRO means ?