What are the steps I need to take after an approved Petition?

Most important, you should listen to your Attorney and get all the documents required, your attorney knows about your case. If you need second opinion, you should contact another lawyer and show your documents.

You should follow the guidance of your lawyer - why else did you hire her if not to benefit from her knowledge and experience?

Your lawyer may be correct and she is not your tax accountant. While the I-130 does nto expire, the support documents must be filed within a year and you must get this in order. You need to listen to your attorney's advice. If you don't like your attroney's services you can hire a different attroney. However, attorneys on are not going to second guess an attorney that represents you especially since we have zero documents to review. You need a consutlation with an attorney to achieve this.

Your attorney can be correct - if the taxes are filed as married, when not or as head of household when, you are not, it can create serious tax issues. Your attorney cannot submit information which will invite trouble. If she says it has to be corrected, go back to your tax preparer and confirm with them.