I just started a small business building and repairing PCs and I was recently hired buy another small business owner. He has 5 computers in his office, all which run Quickbooks. He told me that he wants a server that he would be able to temporarily use as a computer if one of the 5 computers in the offices goes down. I decided that the easiest option would be to build a PC with Windows XP. The PC I'm building will be running RAID to mirror two 500GB hard drives.

Problem is, I've never done this before and I need a way to back up the quickbook information from the 5 PCs over to the new one in the middle of the night. (He leaves his computers on. Not my problem so I don't care)

If I have to buy a program, I can simply add it to the building cost so that's not a problem. I'm willing to spend up to 250 on it but would prefer cheap and efficient. Any ideas?