Is there a way that I can have two media players like banshee with their own library,so that I can import new mp3's without affecting the music which is in my music library which is already sorted?
Unless you tell your music players to sort them, they usually will leave the files' structure on the disk alone. So you can have multiple music players sharing the same library folder, or having different library folders, and so on.
Generally music players will store their library information (which is different from the music file's location) under their own settings subdirectory in our HOME folder. Therefore each player will create an own different library, and libraries from different users will be different too.
Some players (e.g. Guayadeque ) allow to create multiple different libraries.
To avoid updating a library on adding new mp3 files there may be a setting in your player where you can disable auto-updating of the library.