What is average (estimated) cost of replacing the dashboard for this area?

It's just called the cluster; Rebuilt cluster averages $400.00, labor around $40.00.

GM had a cust assistance prog up to 5 yrs 100k miles on this.approx cost parts and labor is about 450.00

Common problem with these 2003 and some 2004 instrument clusters. They can be repaired - it is not a fault of any other part of the vehicle. For repair of these clusters go here: http://www.mrwhizard.com