Recorded DVD copying

Hi guys,
I Have a Pioneer DVD Recorder under my TV - I used it to record some tv-show I like to watch. So I burned three of these episodes to a DVD+RW.
I am familiar with Anydvd,clonedvd2,etc. but when I try to copy it with for example DVD Shrink or DVD Decrypter I get certain errors (I can press retry or cancel but it won’t go away).
I think it has something to do with this.There are two folders on the dvd:VIDEO_RM and VIDEO_TS.
I could copy it using the AnyDVD Ripper and only ripping the VIDEO_TS folder.
Now my question is: Can I add some more episodes to that folder from my computer to burn on one dvd with lost of episodes because it’s a waste to use 1 DVD for like 1.5GB of files. How can I do this?