Currently if sessionStart isn't on the same day as session end (ie 2013-01-20 19:30 & 2013-01-21 22:10) this is what is displayed:

    Sunday 21st of January 2013 from 07:30 PM to Sunday 21st of January 2013 from 10:10 PM

If it's the same date

    Sunday 21st of January 2013 from 07:30 PM to 10:10 PM

---

A better way to handle that would be checking first if it's on the same day, in which case the format will be 

    formatDate(start) + " from "+ formatTime(start) + " to " + formatTime(end)

Otherwise it should be
    "From " + formatDate(start) + " at "+ formatTime(start) + " to " + formatDate(end) + " at " + formatTime(end)