You can file a 'petition to remove conditions of residence', I-751. Once this is approved, you can be considered a lawful permanent resident. There is no requirement that your wife should be working to file this petition. It must be shown though that you entered the marriage in good faith, and there are some ways to prove it. You have to remember that you need to file this petition within 90 days prior to the second anniversary that you were granted the conditional resident status.
You can file your income tax as a self-employed individual.
You may need to consult a lawyer to make sure that you are taking the right steps.
The removal of conditional residence (I-751 form) does not require an affidavit of support. Therefore whether she works or not is not an issue. Make sure you have enough proof about your marriage in the package to prove the relationship including bills, your son's birth certificate, letters or affidavits from friends, insurance, etc. Make sure you also file within 90 before expiry of the card so that you do not have to prove extraordinary circumstances. The removal of conditional usually happens without an interview. But if there is an interview make sure you are ready for it. Our office have filed many similar cases. Please read the information attached.
Shah Peerally, Esq.
Note: The above is provided for informational use only. One should not act or refrain to act solely based on the information above. No attorney client relationship is created until a retainer is signed by both parties