Refering to a Set ActiveWorkbook name in formulas

[s_woodbury]

I have a macro that I run once a month. The macro makes the user choose which .xlsx file to use. Therefore the name of the working file varies. I'm using:
Set CLOloans = ActiveWorkbook
to standardize the workbook name for use in the macro but I'm not sure how to reference 'CLOloans' in a formula. ie:

ActiveCell.FormulaR1C1 = _
"=COUNTIFS([HBSGmoCLOloans]Sheet1!C4,RC1,[HBSGmoCLOloans].Sheet1!C6,"">80"")"

Any Suggestions? Thanks in advance