If having a cup of coffee makes you a better mother, have your coffee. Just be cautious, keep A. eye on baby to see if he is sensitive to it by being fussy or wakeful. If he is, you will need to cut back more. If not, some caffeine is fine. Here is a link to kellymom's website that explains how caffeine metabolizes in good detail and how much is safe:
http://www.mamapedia.com/outbound_link/redirect?link=http...
When they are newborns it takes about 90 hours for coffee to metabolize in their systems, and the caffeine is cumulative. So daily intake of coffee will add up after several days in their systems. Your breastmilk will have the most caffeine in it A. hour after you drink it, so if you can drink it while you are nursing or just before, it will help reduce how much caffeine your baby takes in. And the limits on how much you should drink a day vary, but a conservative safe estimate is about 2 cups a day. When baby is 3-5 mos, you can start having more.
My son was one of those that did seem sensitive, so I rarely had any caffeine. But I did have it when I needed it, and I also ate chocolate. I'm curious how many women who freak out about coffee actually cut out chocolate too. I have actually seen people respond that you should quit breastfeeding if you want to drink coffee. As if formula is healthier than a little bit of caffeine. I doubt that. Drink your coffee and breastfeed your new baby, just be aware of the effects, if any.
I can't answer the sleeping question- my toddler would never be able to share a room with a baby without waking up a million times. Good luck!