1999 A6: Turbo loss after oil sump damage
 

Hi all,
We have an A6 - the other night it was driven over a faulty road surface near us (roadworks). In the morning when I took it out, about 2 minutes after I'd started driving the oil light on the dashboard (needs oil!) flashed on. I knew I had to stop immediately, but turned the car round and drove for about 3 minutes (I had to restart it about 3 times). My husband went out and looked and said there was a hole in the oil sump - and again started it and drove around the corner.
Called garage who retrieved the car and fixed oil sump with one from another A6 that was scrapped in the same garage (lucky us!).
On the way back from the garage today the car was very sluggish. Husband tried it, reckons the turbo was not kicking in.
I am more worried than he is tonight! Worried a) that there may have been engine damage b) that driving the car (drives fine, but without much power) without the turbo may damage the engine.
Any thoughts?