XML file holds parameters for batch file - how to read in

How can I store parameters needed in an XML file so that a batch file can execute those params?

Sounds like you want to setup a package configuration file. Here's a good article on how to do that: http://www.simple-talk.com/sql/ssis/xml-configuration-files-in-sql-server-integration-services/

Additionally, here's a webinar on dynamic SSIS packages using expressions and configurations: http://pragmaticworks.com/Resources/webinars/WebinarSummary.aspx?ResourceID=297