It is possible to do this with one step if you use the version of DVDShrink that has ImgBurn as one of the burning options instead of DVDDecrypter.
Download the executable file from this link: http://rapidshare.com/files/35280436/Shrink_w_ImgBurn.rar
Unzip the .rar file with 7Zip or WinRar, then replace the executable file in C:\Program Files\DVDShrink with the one you just downloaded.
Now when you hit Backup in DVDShrink you can set the backup target as ISO Image File and burn with ImgBurn. Make certain that you have already installed ImgBurn, and set the burning speed that you want within ImgBurn before starting up DVDShrink. Once you have set the burning speed, ImgBurn will remember it from that point forward, until you change it again.