You're going to have to parse the contents of that cell to extract the worksheet
name and the address.

After you do that, you can use:

dim wksName as string
dim RngAddr as string
...some routine to parse those strings
set rsprange = thisworkbook.worksheets(wksname).range(rngaddr)

===
If I were you, I'd use two cells--one for the worksheet name and one for the
address of the cell.

with thisworkbook.worksheets("sheet3")
 set rsprange = thisworkbook.worksheets(.range("b1").value) _
                                   .range(.range("C1").value)
end with

Depending on what the name of that sheet and the address, it could make life
lots easier.