Server Question

I just started using peer to peer in my office. I have 3 computers. We want to share a database between the three. Right now, we can only access the database (ACT) one at a time. If my secretary is using it, I can’t and so on and so on. So, I have asked around for solutions and everyone says to get a server. Is this the solution? If so, may I just buy a not so state of the art p.c. and use that as the server and then be able to access and manipulate the database? I am talking multiple user, simultaneous access. If I get a server, what all kind of equipment would I need?
I humbly thank any response to this question.