android onUpgrade moving some records from old db to new db

What I'm trying to achieve is that my application will ship with an existing sqlite database exported from my web panel with some records(news, products, categories etc.) and later on it will insert some records of its own into it(lets say it'll insert notifications it receives) and it will be copied to the databases folder, up to here there is no problem but my concern is when a user upgrades their application through market I want to replace the new database with the old one but keep those application generated records(notifications it has received) and insert them into the new one. Here's my code so far: (please enhance if necessary)

public class Helper_Db extends SQLiteOpenHelper{

    public static final String DB_NAME = "Test.sqlite";
    public static final int DB_VERSION = 3;
    private static String DB_PATH = "";
    private SQLiteDatabase _db;
    private final Context _ctx;

    public Helper_Db(Context context) {
        super(context, null, null, 1);
        DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
        _ctx = context;
}

    @Override
    public void onCreate(SQLiteDatabase db) {
        try
        {
            copyDatabase();
            Log.e("DATABASE", "Database created");
        }
        catch(IOException io)
        {
            Log.e("DATABASE", io.toString());
        }

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //take out the notifications from old db
        //insert them into the new db
        //delete the old db
        //copy the new db

    }       

    private void copyDatabase() throws IOException
    {
        InputStream input = _ctx.getAssets().open(DB_NAME);
        String outFileName = DB_PATH + DB_NAME;
        OutputStream output = new FileOutputStream(outFileName);
        byte [] buffer = new byte [1024];
        int length;
        while((length = input.read(buffer)) > 0)
        {
            output.write(buffer, 0, length);
        }
        output.flush();
        output.close();
        input.close();
    }

    public boolean openDatabase() throws SQLException
    {
        String path = DB_PATH + DB_NAME;
        _db = SQLiteDatabase.openDatabase(path, null, 
                SQLiteDatabase.CREATE_IF_NECESSARY);
        return _db != null;
    }

    @Override
    public void close()
    {
        if(_db != null)
        {
            _db.close();
        }
        super.close();
    }

}

Thanks in advance.