Google Authenticator old version
Unfortunately, without a backup of the app (Android 2.1+ needed for Authenticator app after 0.62) that you had earlier, you'll need the app APK from someone who still has it or hunt around for this old version.

You can still use 2-step verification by opting to receive the verification code via sms or by using the One Time codes that were generated when you originally signed up for 2-step verification.