I have PF but not as bad as yours. I have found that when it is at its worse, wearing this http://www.return2fitness.co.uk/foot_care/plantar_fasciitis_splint/plantar-fasciitis-splint helps to reduce soreness. I also stretch my plantar fascia, and if I forget, it gets worse. I stretch it by bending the toes back so that the pf stands out. I then add to the stretch by pushing my thumb/few fingers into the pf. Stretches need to last at least 2 mins (not the count of 20-30 that most people suggest - this is not enough time for a stretch to take place). I hold for at least 5 mins, sometimes 10. After a couple of days the soreness eases.
You should also check your hamstrings. I've been studying some anatomy recently it seems that the pf, achilles, calf and hamstrings are all part of one fascial web and that tight hams can cause pf. I've started to do this myself but too early to report.
A good massage therapist might help, but these need to be trained to a high standard (not your local f.e. college course) you can find one here http://www.theisrm.com/directory.php