You can find IRS forms for prior years at the IRS' Prior Year Forms and Instructions page.
You might also consider contacting the IRS's Volunteer Income Tax Assistance (VITA) program, which offers volunteer tax preparation -- including prior year tax preparation -- for people who qualify. Please see Free Tax Return Preparation for Qualifying Taxpayers for more information.
As @DoninGA and @xmasbaby0 indicate above, TurboTax only handles more recent years than you may need.
