Red flashig oil light Audi A3 2.0T FSI 2006

Hi everyone,
we were driving down motorway when red flashing oil light appeared (probably should of stopped straight away) anyway was trying to get to service station wife two kids in car got up slip road around roundabout then car died. AA would not look at it because of red light policy had it towed home, Is a diagnostic check going to tell me anything my feeling is i might have a broken cam belt as it was overdue a change, My dilema now is after reading a fair bit about this sought of problem instead of throwing money at this problem do i jusyt bite the bullet and put a new engine in from a write off Audi, Have been quoted £1900 for 2009 engine 30k miles supply and fit with a warranty or is it worth getting checked out no expert around an engine but have rebuilt a 16v golf engine but was some time ago

Any thoughts welcome
Many thanks
Terry