Assigning A Function To Array?

I am trying to write a code for simulating a stock price using geometric brownian motion. I have the function part down as follows:

Public Function SimStock(Initial_Stock_Price As Double, _
Expected_Return As Double, _
Volitility As Double, _
End_Time_Days As Double, _
Number_of_Steps) As Double
SimStock = Initial_Stock_Price * Exp((Expected_Return - Volitility ^ 2 / 2) * (Number_of_Steps / End_Time_Days) * NRnd2() * Sqr((Number_of_Steps / End_Time_Days)))
End Function

Now what i need to do is to apply this to an array. so that when i run the sub it will simulate prices from today up to some number of days that i specify. This number of days will be equal to "End_Time_Days" which is part of my function. Furthermore the simulation has to be such that it uses the above formula for the first entry but then replaces "Initial_Stock_Price" with the result of the preceding entry in each subsequent entry.