Marketing ROI - How do you track it?

Real Estate Agent with MacWin Consulting

Looking for some help. We have recently started The West Valley Home Team, want to focus on Short Sales, Foreclosures, Spec Homes and Short Sale Listings in Litchfield Park, Goodyear and Avondale Arizona. Our listing agent, Cinda Rose, has her CDPE, CSSN, and SFR certifications. We have signed up as a Zillow Premier agent and working hard promoting the website, We have been considering signing up with as well. My question is how are people tracking their ROI as far as marketing dollars go? I know everyone we've listened to, conferences, books, Ben Kinney etc... has told us that we need to track each dollar that goes out, how it was spent, how many people did it reach, how many people responded to it and how many sales and commission dollars did we generate from it. Is there a piece of software that we can use to track it? A simple spreadsheet template that we can use? Any help would be appreciated.