PowerEdge 1950 HD Swap

I have a PowerEdge 1950 with two SAS 73gb 15k drives. One of the drives failed last night. I have new drives on order as well as the Raid controller battery. My question is about the process for changing these. Should I take the server down, and replace the battery and the drive at the same time? Are the drives hot swappable, and if so should I swap the drive while running first and change the battery later? Any advice is appreciated. Thanks!