Be sure to follow each of the reset steps in the order posted.
Wix has filters for the RX. They are identical to the some of the Highlander filters so a bit of research, or the local Toyota dealer, should have the filters and/or parts at a substantial savings. Even Napa carries the Wix filters under the Napa brand with a single number left off. Try some of these links to see if you find what you are looking for.
http://www.napaonline.com/MasterPages/NOLWelcome.aspx
http://www.napafilters.com/filterlookup/
http://www.wixfilters.com/
Keep records, receipts, and bills to maintain your warranty coverage.
Thanks for the links.