So long as you and your spouse are living together in marital union, you can apply three years from the date your initial conditional residence was granted (this date will be reflected on your current card), less 90 days.
Be aware that any prior issues, even minor, that might impact your good moral character can be considered--failure to pay child support, prior inaccurate statements to immigration, contact with law enfacement, etc... If you have any issues or concerns, check with an immigration attorney BEFORE filing. A person who does not qualify risks not only denial, but in some cases, may be referred to an immigration court for removal proceedings.
This answer provides only general information and may not be relied on as legal advice. For more information about immigration law and policy, please visit www.lichterimmigration.com or follow us on twitter (@lauralichter) or facebook, www.facebook/lichterimmigration. To find an immigration lawyer in your area, log on to www.ailalawyer.com. Listed attorneys have been members of the American Immigration Lawyers Association, the nation's premier bar association for immigration lawyers, for at least two years, comply with annual continuing legal education (CLE) requirements and carry malpractice insurance.