Where to buy dango Japanese sweets

I am staying in Kyobashi very close to Tokyo station and have been looking to try some dango, particularly the multi coloured rice dumplings. Someone had told me you can get them from convenience stores but I haven't seen any.

Where do I need to go to buy some?

Ideally to take away rather than in a restaraunt

Oh, please don't go to a konbini for dango when you're at Kyobashi where all the traditions are.

If you're a first-timer, why not visit Nihonbashi Mitsukoshi department store? On B1 floor, you can choose from the many authentic traditional sweets shops, and they're all to take home.
https://www.mistore.jp.e.az.hp.transer.com/store/nihombashi/shops.html

But what you're looking for is called "san-shoku-dango" which means "three-color-dumplings". Perhaps you're aiming for a more junky type of store. A quick Google search tells me of a place called Takaraya. Click 地図 below for the map.
https://tabelog.com/osaka/A2701/A270107/27056042/

Have fun!

OK thank you for the reply I will take a look and see what I can find!