MacTheRipper and other rip applications "only" copy the content of your video DVDs to your HDD while they circumvent the copy-protection-scheme.
You need Handbrake in order to convert the video on, if you want to save storage space.
Use MRoogle to find many threads about the proper conversion, but combining three episodes into one file might be a bigger hassle than it's worth.
Maybe have a look at ffmpegX.