Can I get a visa once more and marry?

If you apply for a waiver and are able to show extreme hardship to a US citizen spouse (you'd have to be married in order for her to be able to show the hardship as your spouse) then you have a chance of getting the waiver granted.

Yes, if a fiance petition is filed on your behalf and approved you could apply for consideration of a waiver of the "unlawful presence" ground of inadmissibility. As you appear to have remained in the US for more than one year in a period of "unlawful presence," you would be barred for a period of 10 years from returning to the US without applying for and being granted a "waiver of inadmissibility." This waiver would certainly be available to you as the fiance (or spouse) of a US citizen. Keep in mind that you would have to establish that the denial of your return to the US would result in an "extreme hardship" to your fiance (or spouse). Medical difficulties that your fianc? (spouse) is suffering in your absence is certainly a relevant ground upon which this request for a waiver could be made. Before doing so, however, I would consult with a licensed attorney competent in this area of the law. As well, keep in mind that the processing of this type of request can take in excess of one year once the visa application is received by the consulate. The best advice I can provide is to be informed, be prepared and know what you are getting into before you begin the process and start investing time and money into this endeavor.

If she is US citizen, once you marry her, she can file visa petition for you and then, you will be asked to file for waiver at the consulate. Please consult with immigration lawyer as this will not be an easy task.