This will be in your owners manual. You can also see the related question linked to the right for the 2005.
The 2010 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
The 2011 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
The 2009 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
The 2012 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
The 2014 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
The 2013 Toyota Avalon has free maintenance for 2 yr./ 25000 mi..
How do you reset the Airbag warning light on a 1995 Toyota Avalon?
The 2013 Toyota Avalon-Hybrid has free maintenance for 2 yr./ 25000 mi..
The 2014 Toyota Avalon-Hybrid has free maintenance for 2 yr./ 25000 mi..
How to Reset Maintenance Warning Light on a 2008 Toyota 4Runner
I have researched online, and i cannot find an exact maintenance schedule for your vehicle. My recommendation for you would be to call a Toyota dealership near you, and i am sure they can print one out or inform you of what is required at your current mileage.
The 2003 Toyota Avalon runs on premium unleaded (required).