Give some hotel options on Nanjing Road between USD50 to USD 100.

Charms Hotel is suggested for you. It is located at No. 619, Jiujiang Road.
For the attractions, I think the Bund, the Huangpu River, Xintiandi, Yuyuan Garden and Shanghai Musuem are must-see places. Besides, if you have time, you can go to the Jade Buddha Temple, Oriental Pearl TV Tower and Zhujiajiao Water Town.
Hope these information can help you.

Thanks. Also give weather status for these days.
Thanks
S.K.Gupta

It is hard to tell you the exact weather, but generally speaking, October is a good time to travel in that city, it is no use to worry about the weather. For clothes, you can take your T-shirts as well as some short-sleeved clothes.