Wow. That's definitely a holiday mission! It looks like the right time to visit as well, because there are plans for an airport to built over the nexy years and this will certainly change the island forever.

The only way to get there is by sea, usually the last Royal Mail Ship in operation from Cape Town which takes about 5 days and stops at Ascension Island.

http://www.sthelenatourism.com/pages/tour_operators.html

Here's a link to the RMS site too: http://rms-st-helena.com/

Good luck!