Your choice is limited, but the following categories still have usable versions:
Direct search query: “com.android.vending 28.8.12 apk” play store download for android 4.1.1
You will need a way to locate the file once you download it. Most Android 4.1.1 devices should have a basic "Files" or "My Files" app pre-installed. If not, you may need to download a lightweight file manager via your browser. Your choice is limited, but the following categories