I convert flac files with my
foobar media player. I believe flac to ogg (f.ex) functionality comes with the install (check options when installing), but if you need mp3s, you may need to download an mp3 encoder, f.ex lame mp3 encoder, which you then point foobar to when prompted.
As for splitting up flacs from a cue file, I just use
medieval cue splitter. It's free, simple to use and does the job well.