Dear Dave,
You can get S&P data from
http://table.finance.yahoo.com/k?s=^gspc&g=d.( I'm sure other sites will do the same). You choose the time frame you need and then download the data and finally import everything in excel using the "tools" bar then "External data" then "import".
Anyway you'll still need to handle everything manually since COT reports were only bi-weekly until 9/92 and then weekly.
You get open-high-low-close so you make nice graphs.
If you have any questions please feel free to ask.
Cheers
Denis