Mechanic Q: 2002 Audi A4 1.8t awd quattro needs some fix ups?

the oil warning light is on, but the level is fine. could this be a sensor issue? i have a squeeky exhaust system that makes a ton of noise whenever i go over bumps, potholes, and general daily driving. is this an issue of metal on metal rubbing or a bushing issue? i need to replace the front motor mount, what is the best way of doing this if i only have one shop jack and one standard lift jack (standard tire change jack)? there is a minor oil leak, very minor but nonetheless is there, what is the best way of finding out where the orgin is? should i do an undercarriage clean? car has 184647 miles on the engine and chassis; what services do i need. i have not had any regular maint. for at least the past 50k miles.

A: 2002 Audi A4 1.8t awd quattro needs some fix ups?

what do you suppose is a good guess on maint and repair cost? 2k-3k?