If my husband sponsored his ex wife's green card in 2011, can he sponsor my green card again and how much is sufficient income?

A U.S. citizen indeed may sponsor a spouse for adjustment of status, become divorced and re-married, and sponsor a second spouse for adjustment of status. In connection with the second adjustment of status case the USCIS can be expected to apply significant scrutiny to assure that BOTH marriages were bona fide. In connection with the second adjustment of status case, the U.S. citizen will need to file an Affidavit of Support for the second spouse, and will need to provide documentation of adequate income to meet the specifications on Form I-864 Poverty Guidelines for the applicable family size. The continuing obligations relating to the first spouse will require that the first spouse be included in calculating the applicable family size. If the U.S. citizen does not have sufficient documentable income, it will become necessary to have a joint sponsor in the adjustment of status application process. Generally the joint sponsor may be any U.S. citizen or Permanent Resident with sufficient documentable income who is willing to assume the responsibilities specified in the Affidavit of Support. Especially with issues as potentially complex as those mentioned in your question, it would be wise for you and your husband to work with an immigration attorney.