You may want to go to Izmailovsky market to buy your souvenirs. There are more shops and better bargaining compared to old Arabat street. The market is easy to reach via the metro.
Take the metro to the Partizenskaya station. In Russian, the name of the station is written as Партизанская.
As you step out of the station, look to you left. Diagonally across the street you will see a gate with Russian letters around the frame.
Walk towards this gate.
The large shopping mall in this complex (about 70 meters to the right of the path to the market) has restrooms, ATMs and some fast food restaurants.