Bad oil pressure? Is it just a clog somewhere? or a new pump is required? I'd get a second opinion if possible before deciding.
If I were you, I'd run engine flush a few times first. LiquMoly has a good reputation. I used it on my car without any problems. When I took off my upper timing chain cover last month, the engine looked very clean and new!
Also, how much can you buy a 2013+ A5 for in your market? 2013+ engines are supposed to have fixed most of the engine-related issues (i.e. tensioner, timing chain, intake manifold, HPFP, etc.)