I presume you want to Pull information from the Windows box and not have a Snare Agent push it to MARS.
The Snare agent is free from:
http://www.intersectalliance.com/projects/SnareWindows/
Depending upon how much reading you want to do outside of the Cisco Install and Setup guide, there are plenty of resources available:
1. From the Cisco Press, Security Threat Mitigation and Response (Understanding CS-MARS) by Dale Tesch
2. http://ciscomars.blogspot.com/
3. http://www.demolabs.co.uk/ This has some excellent online demos.
4. http://groups.google.com/group/cs-mars-ug?hl=en-GB
This is a User Group with some very good postings.
Hope this helps.