Dashboard display upgrade

This is probably a dumb question, but I thought I'd ask... I have a stripped down base model and realized that my only display options on the dash are total miles, trip a and trip b. I like to monitor my average mpg and was wondering if there was a software/chip upgrade? Hell, I don't even know if that's what you would call it. Any help would be great.
Thanks!

 

Thanks for the help. I did some research and found an aftermarket solution. I might give it a try.

http://www.scangauge.com/products/scangaugee/

 

I use one of those in my car to monitor temps and the fuel mileage functions are pretty cool.

 

Had mine for almost 4 years and love it.

 

Why wait? $45.

 

or you know, use a BT elm327 adapter and a cellphone app.