Plantar faciitis is typically a stuborn pathology and can take 12 months or longer to resolve. The important thing is to address any biomechanical factors that may be contributing to the problem, otherwise the condition may take even longer to resolve. I would suggest it is worth while being assessed by a quality sports physio to determine what these are in your case.
In the meantime taping for the foot can provide some very effective pain relief but this is usually only helpful while the tape is on. Again a sports physio can show you this if you haven't already tried it.
For now I would be religiously stretching your calf muscle with the knee straight and the knee bent to try and improve some of the tissue extensibility in the calf/achilles/plantar fascia complex.
I hope this helps?