You can bring your wife either on tourist visa (14 days and can be extended more 14 days) and you can do other 2 tourist visa on same without exit from Doah...Its need only your passport copy (RP or work visa approved with the form)

And other with the visit visa (6 months limit and can be extend more 1 month without exit from Doha)...but after completion of this limit...Only you can do other visit visa after three months of her exit....Not prior to that....This no need any bank statement..Just with the form you have to attch your passport copy, I.D copy and No objection letter from your sponsor...

Let me give you one suggetion for your future: After spending more than 6 months here in Qatar...You can apply for the residense permit for your family....In that case, 6months bank satement need...But some time three months bank statement also work.. but this process is legthy and need more saveral papers.....

Have a nice day and best of luck.....
If you need more help. you can contact me on "[email protected]"....