You can find some information on HELLP-specific recurrence from one of the experts here:http://www.preeclampsia.org/forum/viewtopic.php?t=3387
I would ignore the bit about anti-oxidant supplementation since more recent research has suggested that it is not helpful. There are also more recent studies on the "two-year window" that do show a reduction in the chances of developing pre-E. Pregnancy causes a remodeling of the spiral arteries of the uterus, and some of the "remodeling" persists for a few years after pregnancy. These remodeled arteries can facilitate better implantation of the placenta, which can reduce the odds of PE.
We haven't tried again. You should get some responses from women who have decided to have another child. We have posters with second pregnancies that went perfectly, some that still got a milder case of PE, and other who got really sick. Many women have had healthier/easier pregnancies after a HELLP pregnancy.