Yes, you may apply for your wife as an LPR, but then she would fall under the 2nd preference category, and will have to wait a couple of years until a visa will become available in order to obtain a green card. If, however, you will become a US citizen, which appears that you are already eligible for, you may apply for her as well, and this way she will be considered your immediate relative, and a visa will be automatically available to her, and you will save a lot of time.
Contact attorney Gintare Grigaite, Esq. at 201-471-7989, located in New York and New Jersey. Answers on AVVO do not constitute legal advice and do not form attorney-client relationship. Always consult an attorney for a legal advice.
You can petition for her, but as an LPR you will have to wait for a visa number to become available, which currently is taking a little under three years. If you become a United States citizen then there would be a visa number available immediately and she could do the adjustment of status. It's very important that if you do the petition as an LPR she doesnt overstay in the US, otherwise she would have problems to get her green card in the future. Consult with an experienced immigration lawyer to evaluate the circumstances of your case.