I would say sell it and buy one that is in better/running condition. The 86 I had sat for many years before I rescued it. It did have sentimental value but there is a point where that doesn't make it worth it anymore.
The major stuff like engine and transmission adds up quickly but the small stuff will nickel and dime you to death.
My old car ended up needing a transmission ($3500*), then a motor ($7500*), new cooling system ($800), new turbo ($800), new power steering system ($500), new fuel system ($600), new shocks ($200), new tires ($500), new ac system ($800), etc. That was just the stuff to keep it running. There was another $600-700 in the interior for carpet, headliner, re-dying stuff, etc. The to-do list when I sold it was also growing; it needed new rear gears because of a howl ($850*).
*=done by a shop, otherwise I did it. Stock rebuilds would be a bit cheaper but getting it done right is still not cheap.