Re: 2 1/2 month old only nursing every 3-4 hours!!
If her diapers are frequent enough and she's gaining appropriately ... then just feel lucky you got an easy 3rd baby! And remember it'll probably change in a month or a week 
However, I might be a little concerned that she's doing a low-level nursing strike of some sort, if she will only nurse when asleep or groggy. Is she a laid-back baby in general? Any other weird behaviors? The good news is this will probably help with your OS/OALD, right? Maybe she'll get more interested when she doesn't have to deal with that?
DS 6/7/11 - Still night & morning nursing, but the rest of the time he just doesn't have time for me! After mostly working at home, gleefully packed away the pump at 11 months.
Another on the way in October 2013!