Copying formulas from one spreadsheet to another

I have set up a spreadsheet which has data in twelve different sheets (one for each month). I also have a summary sheet where I use the vlookup function to pull totals into it. I have this working for one of our products. I am now working on setting this up for another product. Instead of going in and writing all of the formulas again for the new product I would like to copy the formulas from one spreadsheet to another. When I do this the formulas refer back to the other product's spreadsheet instead of referring to the sheets of the new product. Is there a way to avoid this from happening so that it refers to the sheets of the second product but keeps the rest of the formula intact?