You may be eligible to obtain an immigrant visa, based on your marriage to a US citizen; however you may be subject to one or more bars to admission for periods as short as three years (i.e. in the US in unlawful status over between 180 days and 364 days) or as much as a permanent bar to admissibility (i.e. false claim to US citizenship). The answers to several questions can have significant bearing upon if and when you can return to the US as either an immigrant or even a nonimmigrant in the future. Questions, such as, “What was the ground for removability –merely unlawful status/overstay or for commission of a crime? Have you ever been charged and/or convicted of any Crime(s)? If so, what were the nature of the offenses and when did they occur? Did you ever claim to be a US citizen to obtain a job in the US? Did you check the “citizen or national” box on the I-9 Employment Eligibility form at any time? Did you ever use a US birth certificate or passport to prove employment eligibility? Waivers may be filed for one or more bars, should they exist, which will permit you to reenter the US as an immigrant (permanent resident) once the waivers are processed and approved.
Reliable advice cannot be given until all the pertinent facts about your case are known. The best place for you to begin is to file a Freedom of Information Act Request (Form G-639) with the USCIS and Immigration Court, to obtain a copy of your immigration file so you know your immigration-related history without a doubt. Unfortunately, this can take several months to obtain unless you have a humanitarian reason for expedited processing of your request. Even before obtaining your immigration record you could consult with a lawyer to discuss your case but possibly refrain from filing any petition or application until you know your immigration history with greater certainty unless you are willing to assume the risk that you have a correct understanding of your immigration history.
Assuming you are admissible as an immigrant because of your bona fide marriage to a US citizen, it will also be necessary for your spouse and you to show your intent to return to the US and to reside here when processing for an immigrant visa at the US consulate or embassy. Your application will almost certainly be denied if you intend to obtain a permanent resident card as a convenience to come-and-go from the US with no intention of abandoning your residence in your home country rather than applying for residence with the intention of living in the US.
You will need to file an I-130 (petition for alien relative). If you have a ban on you from your previous overstay then that will likely have to be honored. You will need to fill out the petition and provide the requisite paperwork and filing fee to USCIS. Much documentation is necessary to provide proof of a valid marriage. USCIS is very wary of sham marriages entered into for the purpose of gaining citizenship benefits. This is why I would suggest hiring a lawyer to get the paperwork together so that a proper and successful filing of the petition can be done.