Install Google Analytics to my OSCommerce to track conversions

I've got a highly modified OSCommerce shopping cart that I need the Google Analytics code installed into. I currently have the code in the footer of the store for general analytics, but I now am starting some additional marketing of the store and need it added to the cart in order to track conversions. My store is highly modified and this job should be considered to be manual, there will be no drop-in contributions that will work without breaking my store here. I would expect that this should be a quick and easy and low cost job for the proper candidate. thank you for your bids.