hi,
I believe you won't catch (recognized) any face with existing analog camera + DVR,
those analog system only let you know the human or animal or car etc... that's all you could get..
because I been faced quite similar situation like you and I changed whole system with HD camera + HD DVR which is using coax cable, and the result was very clear... i think it's much better than megapixel IP,
if you see the image quality of HD camera + HD DVR then you won't never buy analog system..