For the speaker, you're going to just have to watch eBay for piece-parts radios. It maye be a long wait and tought to find. You are also smart to post here; Someone may see this post in time and pop up saying they have one and are willing to sell it.

Sometimes I find parts of the era that are suitable replacements. Tubes, caps and coils are relatively easy to replace with new or NOS parts. But sometimes the speaker is best repaired or replaced with another from a salvaged radio.

About the power supply, you might make a simple rectified transformer suply. That's pretty easy. Do you happen to know what voltage(s) you need?

Wayne