LOOKUP (modifying formula)

[donyc]

I am having really hard time modifying this formula..it returns values from K8.. but I only need it to return values if my column in previous day tab R8=New York.. Any idea how to edit this? any advice is much appreciated! thanks so much

   "=IF(ISNA(LOOKUP(2,1/(A2='previous day'!A$8:A$" & LRDat2 & ")/(C2='previous day'!C$8:C$" & LRDat2 & ")/(M2='previous day'!M$8:M$" & LRDat2 & "),'previous day'!K$8:K$" & LRDat2 & ")),""1"",LOOKUP(2,1/(A2='previous day'!A$8:A$" & LRDat2 & ")/(C2='previous day'!C$8:C$" & LRDat2 & ")/(M2='previous day'!M$8:M$" & LRDat2 & "),'previous day'!K$8:K$" & LRDat2 & ")+1)"