Android sqlite database add method

public class DatabaseHandlerForBalance extends SQLiteOpenHelper {
    public static final String KEY_ID = "id";
    public static final String KEY_RubBalance = "rubBalance";
    public static final String KEY_DollarBalance = "dolBalance";
    private static final String DATABASE_NAME = "newUser";
    private static final String TABLE_NAME = "Balance";
    private static final int DATABASE_VERSION = 1;
    public DatabaseHandlerForBalance (Context context){
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_BALANCE_TABLE = "CREATE TABLE " + TABLE_NAME + " ("
                + KEY_ID + " INTEGER PRIMARY KEY, " + KEY_RubBalance +
                " INTEGER, " + KEY_DollarBalance + " INTEGER " + ")";
        db.execSQL(CREATE_BALANCE_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS" + TABLE_NAME);
        onCreate(db);
    }
    public void addBalance(BalanceTable balanceTable){
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(KEY_DollarBalance,balanceTable.getDollarBalance());
        values.put(KEY_RubBalance,balanceTable.getRubBalance());
        db.insert(TABLE_NAME, null, values);
        db.close();
    }

} My code of database handler. I want to write method that adds balance in dollarbalance and rubbalance columns by id. How can i do it? Thanks