My period is 10 March to 16 March and my next period will beging 7 April 2013 "28 days cycle" when should we try for a baby girl?

It's all Luck of the Draw.
You get what arrives..

There is no "time" for a girl, it is all in the sperm and conception. You do need to track your real ovulation dates ( not online tracking) and time sex right before ovulation.

As far as girl or boy, short of medical labs there is no girl time