Starter/Oil Leak

I have a 2001 Galant with 175,000. About 7 months ago I had to put ina new starter. Mechanic told me that oild was leaking onto it and that fixing the leak could "turn into abig job". Last week, started failed, A new one is was put in. Turns out that the leak, according to this mechanic, is in valve cover. He told me that it would be about $2000 to fix. I'm reluctant t to invest more in this car. My question is....how much longer, generally speaking, can I expect thsi new starter to work, with continuing oil leak. I drive a lot.

Any feedback, will be appreciated