HI Dear Sir/Madam
Well right now I am just a green card holder so I got to go more three year to get my US CITIZENSHIP and after that I will become us citizen and I am thinking to get married back home with mine girlfren and she is in ASIA .I was wondernig how long will it take her to get us citizenship and what are the process I need to follow and what document that I have to prepare so that she can get visa for united staets of america

I think you have to get married first then petition her as your spouse. Or you can petition her as your fiancé and have her come to States and marry her here.