I believe the post on my '79 sport is 1" in diameter. What kind of options do I have for getting a new seat post and saddle for this bike?

Currently, I think the part of the post that secures the saddle has a busted part, because no matter how tight (or well cleaned & greased) the saddle securing bolt, the saddle still shifts a lot when riding (enough to be measured in inches of movement, not degrees). So I'm looking to replace.

Thanks in advance for help here.