Re: Failure to launch Ubuntu Software Center
First, Welcome to Ubuntu and the forums!
Installing with the Software Center or apt-get from the command prompt should give you the same result. Dependency handling is the same under-the-hood. I'm not sure why you had trouble when you installed through SC. Perhaps a verbatim quote of the error message would be helpful.
The package name of the GUI you're looking for is r-cran-rcmdr, so you could install it thus:
Again, you should be able to install it through SC and get the exact same result.
sudo apt-get install r-cran-rcmdr
Jane, stop this crazy thing!