That's a shame, if the car doesn't warrant spending money on. Rust is the killer here in the UK, but it all depends on the condition of the rest of the car, and its faults.
If the car was a decent example, I wouldn't give up even if the engine was dead - good secondhand replacements are cheap to buy here as they are generally so reliable. Not so good, of course, if you have to pay for a garage to do the work.
There's some threads on here regarding idle issues, might be worth a read.