First I wanted to say if you are thinking of co sleeping try the Arms Reach co-sleeper. It was a godsend with DS2. Second to answer your question it took 8 wks with DS1 and DS2 had colic so that was a lot longer. It took 2 weeks to "heal" so I would definitely say 2+ another 2, if you can take that much, is minimum. I think you can only start feeling normal again when you can get sleep for a block and that was at 4-6 months.
Thanks ladies - Im not even pregnant yet ( that i know of ) but already looked at co sleepers but as space next to my bed is limited ( just big enough for moses basket ) im limited to the ones i can use but I have seen one that is perfect called the NCT bednest - BUT it is super expensive !!! Last baby - not sure i can justify spending that much but I guess I will get some of it back selling it on afterwards so I think im going to keep an eye out for one. :-)