No, you can’t use your income to supplement an I-864 Affidavit of Support, because the document requires a permanent resident or U.S citizen to support you in the case you lose your job and need help supporting yourself. If your wife didn’t earn more than 125% of the federal poverty level for your household size (ex. $20,575 for a household of two) you’ll need to get an additional affidavit of support from another relative (who is a us citizen or permanent resident) perhaps her parents, etc