I’d fix the car and advise getting a few more estimates. The oil sender is no big deal and while the brake booster (if that’s really the problem) is doable at a cheaper price in my opinion.
Heck, if you’re disillusioned with the car and anywhere near OK I’d be interested in it for 250 rather than dump it at the boneyard.
I do wonder why an engine failed at comparatively low miles as SAAB engines and transmissions are very reliable.