I'd look into getting it fixed. But I'd probably get a second opinion on the sensors issue too. Even with the $750 bill it would probably be more profitable to fix it and sell it as running rather than scrapping it. You probably wouldn't get more than $1000 if you sold as a non-running vehicle (less if you sold to a junk yard) while you could probably get $2000 - $2500 if you sold it with the flaws you mentioned but still running. I've sold two cars, a '93 Accord with 190K miles and a '94 Altima with 160K miles, both with significant flaws and a lot of miles, both for over $2K.

Fix it, polish it up and post it up on autotrader and you'll probably sell within a month. There's always been a large clientel for cars in that price range.