Regrouping Family(Reminder)

Hello

This is writting to get some information pls
I have residency Permanent comunitario(validity 10years). now divorced.
I have my family in india also. Now i want to apply visa for my 02children also. no wife. I have permission letter by my wife to apply visa for childrens. My questions are

1. Can i apply for my childrens (They borned before my marriage in spain).

2 Pls give me detail of required documents.

3.where to apply in ministry OR for me there is another process to apply as i have residency permanent comunitario.

4.what is the importance of salary slips because for renta 2012 i have income only 9500 to 10000 euros. But from Feb2013 I have pay slip of 1400euro/month.

5. After how much pay slips (in may/june) i should apply for my children visas.

It will be higly appreciated if u guide me as per my questions step by step.

Thanks and awtg.