I doubt you will find what are you looking for.

Sleeping bags are available but you might need to have at least 3 season for winter hike. Trekking sticks and some good stuff is available in the new sports shop in Villagio, near food courts. Expensive shop but some good stuff is there.

If you are not able to find good clothing, go with the layers. The best thing (if you can find) is breathable wind breaker/rain jacket.