Pivot Table with Data Model Connection - getpivotdata #REF error

The problem I am facing with getpivotdata() is that the arguments in the getpivotdata are referencing the columns in the data model/SQL Server. 

e.g. 
=GETPIVOTDATA ("[Measures].[Count of Activity Type]",'DD View Pivots'!$A$3, 

"[v_rpt_ActivitySummary].[Area (Regarding)]","[v_rpt_ActivitySummary].[Area (Regarding)].&[United States]", 

"[v_rpt_ActivitySummary].[Note2]","[v_rpt_ActivitySummary].[Note2].&[Calls]", 

"[v_rpt_ActivitySummary].[Week]","[v_rpt_ActivitySummary].[Week].&[This Week]") 


When I try to change the item reference to certain cells in my output dashboard I get a #REF error. 
e.g. 

=GETPIVOTDATA ("[Measures].[Count of Activity Type]",'DD View Pivots'!$A$3, 

"[v_rpt_ActivitySummary].[Area (Regarding)]",G$2, 

"[v_rpt_ActivitySummary].[Note2]",$C5, 

"[v_rpt_ActivitySummary].[Week]",$D7) gives me a #REF error. 

I would like to change the Items in my arguments into cell references. Is there any way to fix this reference error? 

Thanks, 
Nirmalya.