Can we sponsor her sister and brother for their green cards if my wife received her green card in 2012?

If you own or control a business that has a legitimate need to employ either one of your in-laws, then your wife's immigration status is irrelevant, because the business will be sponsoring the immigrant visas, not your wife. If you do not have a business that could sponsor your relatives for employment-based immigration, then your wife will have to become a U.S. citizen first, because U.S. permanent residents cannot petition the government for their brothers' and sisters' immigration. Your wife can file an application for naturalization 4 years and 6 months after receiving her green card. However, you need to understand that the family-based immigration category F-4, "brothers and sisters of U.S. citizens", has many times more applicants than the number of visas allocated each year; as the result, your in-laws will have to wait for their immigrant visas. Right now, visas are being issued to the citizens of the Philippines who had their F-4 immigrant petitions filed in April 1993. Although the queue moves a bit faster or a bit slower at times, its advancement averages out to the speed of the calendar, which means that, unless the immigration process in the U.S. undergoes some major changes, your in-laws could receive their immigrant visas about 23.5 years after your wife becomes a U.S. citizen and files immigrant petitions for her brother and sister.