Hm. Well, i am not sure about womens sizes, but I know that for me, I use a 154-158 board, and those generally fit medium bindings and boots, so probaby size 7-9 mens.
So if yours is 147, i would think it would fit mens small boots. 6.5 ladies is like 8.5 mens right? If that is the case, then that would be in the "m" or "medium" range, so id think it would be a little big for your board.