planning to see doc. potter in april

i am back on this website after having swayed for the last 2 boys. i have three total. :) i love them to pieces and cannot imagine my life without them, but i still dream of a little girl. i have a consultation with dr. potter in april.
FIRST QUESTION-
what would you say is the average amount of cycles people must do to get their desired gender? i have cycled once before but only had one normal XY. i am willing to try a couple more times but really pray it will happen this first cycle.
SECOND QUESTION
any recommendations on supplements to increase chances of healthy xx embryos? supplement for both myself and DH?
thanks