Check this link for the amount of income needed:
如果附上他们在中国的美元存款,有必要吗?
-Their deposit can not be used for their green card application. By the way, you don't need to provide I-864 and the support documents until your I-130 priority date is current.
若有必要,是中国银行,农业银行的账户,都行吗?