I've just created a quick and dirty import tool. It is just an .aspx page with inline code, you can download it from here. Extract it and put the EventImporter.aspx in the root of your site and navigate to it logged in as admin. It should work but you may want to try importing a single event first to make sure the time is correct and if needed you could adjust the code. If it works correctly for the first event just delete it from Event Calendar Pro then use the import all button. Keep in mind that the free Event Calendar did not use UTC, but Event Calendar Pro stores data in the database as UTC and adjusts them to the correct time zone for display.
Hope that helps,