There's no magic answer.

First of all, you really need to give more information in your question. What type of rear suspension? Leaf, coil-over?

Assuming it's a leaf spring suspension, cut the spring mounts off, move them to the proper location (or make new ones) and weld them back on. Take the driveshaft to a good shop and have them use the old yokes on a new tube. That's the easiest and least expensive.