SmartHeap
You might look at Stratosware's "C-Heap Standard" – it's only $99 (+$40 for
source). I haven't used it, but find their Memcheck memory management debugger
an excellent product so I'd have considerable confidence that it would work
well. Contact them on 70244,1372. Good luck. (NB I have no ties with the
company – I'm just a satisfied user of Memcheck).