The weather is a little cold these days, but not sure about the days you'll arrive here. Better bring your sweather with you, and coat or jacket, keep noticing the forecast before coming.

Don't worry about the weather, if you bring just a sweater there's a ton of jackets and sweaters you can buy at the 'fake markets' (where I'm assuming you would go to get childrens clothes).

I would recommend Science and Technology Museum on Metro Line 2. The market is literally right there and great prices.

The alternative is Tao Bao City between Nanjing West and Peoples Square (also on Line 2)