Since you already removed the condition from your lawful permanent resident status, your immigration status is no longer tied to your ex-husband. Just comply with all of the requisites for maintaining your lawful permanent resident status, and you can keep it indefinitely. As for citizenship, the general rule is that you can apply for citizenship after you have been a lawful permanent resident for five years. If you acquired that lawful permanent resident status through marriage to a U.S. citizen, then you can apply for citizenship after you have been a lawful permanent resident for three years.
You can only apply for naturalization after 3 years if you are still married and living together with your husband. Since this is not the case, you can apply after you have been a permanent resident for 5 years.