How to Setup Cube for Queries between 2 Dates

I have setup a simple cube for school admissions data and the end user will be using Excel or SSRS Reporting Manager to access the data. 

The question I have is how to calculate applications (for example) between two date ranges so that the end user can do the same. 

I am not sure if I should be using MDX to create a calculated member or if I should go about it a better or easier way.

Here is some MDX code that I have been playing and seems to work...

 WITH MEMBER [MEASURES].[COUNT] AS 
Sum([Dim Date].[Date].[Full Date].[2012-03-01 00:00:00.000]:[Dim Date].[Date].[Full Date].[2013-11-24 00:00:00.000], [Measures].[DISTINCTAPPLICANT])
SELECT {[Measures].[COUNT] }ON COLUMNS, 
{[Dim Applications].[APPL START TERM].&[2013AY]} ON ROWS
FROM [FACT_ADMISSIONS]

Unfortunately, if it's the calculated member that I should be using how would I set it up 1) to have date and start term parameters and 2) how would I set it up so that an end user would be able to pick the date ranges say in Excel?

Thanks.