i do not have any recommendation for the hot springs in Chongqing as the ones that i went to are below standard. the outfits that i went to r standalone spas, outside hotel setting. i was staying in hotel in Nan-an area then. if u wan, u can refer to lobangs on a local website (
http://www.xht2.com/list/?html=9).
As for 1 day tour around Chongqing, u can go to Daizu Rock Carvings(A series of Chinese religious sculptures and carvings, dating back as far as the 7th century A.D., depicting and influenced by Buddhist, Confucian and Taoist beliefs. Listed as a UNESCO World Heritage Site.) I get my hotel to arrange for the day tour previously, with tansport n lunch included. Alternatively u can also go to CiQi Kou, which is a 1000yr old town. U can flag a cab to go there n u dun need full day to tour that place.