SSRS Date parameter - current month from SSAS cube

I have a SSAS cube with a date dimension called Posting Period and now I would like to have my report parameter using this date dimension to show the current month.

So far I have worked out the following expression which are working(Fiscal year calendar going from May to May) for the year component - but I can't figure out how to get it to work on Quarter date part (and the month) so as you can see the Quarter and month is hardcoded in the below expression:

="[PostingPeriod].[Posting Period].[Year].&[" + CStr(Year(Today())-1) + "].&[Q4].&[10]”

Any help would be appriciated.

Tx