D.H.
Two bedroom is really all you need and it will certainly help you out financially. There have been plenty of people that didn't get their own room and they were fine.
Now, as far as how mean the 2yo is with her sister....well, is the older one getting attention? Are you making statements like...'I can't do that with you, I've got to tend to the baby', etc. That puts the problem on the baby, so the older child will resent the baby. It just needs to be worded differently. I don't if the resentment can be turned around now, but I would certainly redirect her attention to something else and spend time with her as much as possible. Hopefully as time goes on and you spend time with them both together and reword things differently (blame it on yourself), she'll come around to loving her sister.
Fortunately, I've never had that problem with my own kids, but see that with my friends' kids....there is that common denominator from what I've seen.
As far as the sleeping arrangements...I would put the crib in YOUR room and let the 2yo have her own room. That way, you can monitor the baby in your room AND you can put one of those child proof caps over the doorknob when she is taking a nap so the 2yo can't go into the room. Good luck!