There’s a nice family owned store with a decent selection of children’s books (not comic books – real books) in English and Chinese (some local books and some translations of good foreign books) a few blocks behind the Formosa Plastic Bld, which is next door to Changung Hospital on Tunhua N. Rd.
Unfortunately I don’t know their hours, which seem to be slightly unreliable. But if you’re in the area, there’s a road that exits onto Tunhua, which separates the hospital from the Formosa Bldg. Walk down that road away from Tunhua just a few blocks, past a little park and a Royal Host restaurant till you get to the first traffic light and the store will be just on the other side of that intersection on the left.
Or, if that’s too much trouble surely Eslite and Kingstone have lots of children’s books. Actually, I remember noticing the decent selection of children’s books at Kingstone on Minsheng E Rd, not too far from Minsheng Circle.