Hey, I got the answer.
i am adding answer here, if anyone wants it.
After doing regression in ANN tool of matlab using "nnstart" command. at the end they will ask you to save " Matlab function", so you can save your matlab function with appropriate name. so, later you can use this function to predict any in between values.
by Calling that function with those input(s).
Sorry for the inconvienience if i have wasted your time by asking this above question.