Assuming you have established that that RSS feeds are available, then you can use wget to obtain the RSS feed contents. You will just need the URL of the feed corresponding to each time period that the feed covers.
RSS feeds usually terminate in .rss or .xml, so an example would be:
wget http://thewebsite/2008/01/01/therssfeed.rss -O thewebsiterssfeed20080101.txt
This saves the RSS feed found the this url to a text file. Note that RSS feeds can overlap so some de-duplication may be required.