Usually when the master is bad you'll see fluid just beneath it on the booster.
If it were me I would start buying part's now and come next spring replace everything shoe's all 4,hardware and springs,wheel cylinder's all 4,master cylinder,all the steel lines and rubber lines.
Then replace all the fluid.
You certaintly don't want any brake issues either will driving or when you want to drive and you can't because you have brake problems.
That's what I did on my bird.