I agree with others, it doesn't hurt to approach GM and request help out of warranty. Worst they can tell you is "no". Even if they go 50/50 with you, it might be worthwhile to get it fixed and then trade in if you still decide to upgrade your truck. The value of the repaired truck will likely be sufficiently high enough to justify your investment.
Option #2 would be to go through insurance.
Hope you get it figured out and come to an acceptable solution. For what its worth, I LOVE my Ram (bottom of the line and still a great truck) and we don't have that CP4 injector!!!