I am legally blind and unemployed, my wife overstayed her visitor's visa and I would like to apply for a green card for her is that possible

Are you a US citizen? If yes you can sponsor your wife for her green card even if she overstayed her visa. If you're unemployed you would need to get a joint financial sponsor. Discuss your case with counsel in a free phone consultation. Some of us charge a very affordable flat fee for representation from start to finish and counsel anywhere in the USA can represent you.