4.10 Rear End Vs. 3.55 Speedometer

[Old Yeller]

New to the site and wondering if anyone might have some advice for updating the program that would bring my speedometer and odometer in sink with the 4.10 gears that the previous owner installed. I just purchased a 2006 GT and have heard about the Bama Tuner being able to do this, but wondering if there is another way without spending $400+.
Thanks for any feedback!