Ipod + ITunes = aaarggghhh!

It used to be that when I subscribed to a podcast it would automatically add it to the Recently Added folder, but now I have to collect it from the library section. Then if I drag it in the designated folder I created i get a message along the lines of "duplicate file, do you wish to proceed?" I have to select yes to get the new podcast into that folder but then it seems to add all the previous files again. The result is everytime I get my weekly podcast I put the latest one in the folder plus the old ones again. The file then has 1 episode of 04 August, 2 episodes of 29 July, 3 episodes of 22 July etc etc. If I try and uncheck oneof the podcasts it unchecks them all.

Does anyone know what I am doing wrong??