Tokyo has an excellent public transportation system with trains and buses readily available. We suggest purchasing a Pasmo or Suica card (2000 yen initial fee: train fare + deposit) which can be used on all public transport in Tokyo. Depending on your route, expect to spend around 2000-3000 yen per day on transportation costs.
If you have more time, consider exploring Tokyo's themed cafes, such as a cat cafe or maid cafe. For less time, skip the Robot Restaurant and replace it with a visit to the Tsukiji Fish Market.