I am under processing in National visa center. This year my annual income is $ 12,000 beause I was out of country for six months. I have ballance & more than $8,000 in my account. Now, my corrent annual income would be more than & $20,000 by end of the year. In this case could I sponsored my wife? Please share me if anybody have a good idea. thanks. 

Yes you can. Ask your employer to give you a letter stating your estimated annual income for this year. When you file for sponsorship submit that letter including the letter from your bank that shows your account balance. Ask your bank to give you a letter. They usually mail within a week. Your total income would be around $28000 that should be enough for you and your wife.