Networking :: Book Recommendation / VPN Network Maintenance

I work for a small retail company which until recently consisted of just one location. This month, we will open two new stores.I have been given the task of setting up a VPN network between the three locations and maintaining it.This network will consist of a main data server on the original location which has four client computers.The second location (another part of town) will have three clients, and the third location will have one client, all connected to the main data server (Retail POS system.) This will be a hardware VPN, with the main data server and all of the client computers running Windows XP.I have been working with the telecom company that is installing the phone system and is providing the routers at each location for the VPN.

I realize that since these are all Windows based machines it is not a Linux question, but I know that many of the experts here maintain Windows machines as well in their work. I am not an IT professional (I am a gemologist), but because I have been a Linux user for most of the last ten years, my boss seems to think I could handle this task so rather than contract this work out, he has asked me to do this. I truly enjoy this type of work, but I am concerned that my lack of knowledge is going to catch up with me, even though I do have a fairly good basic knowledge of Linux networking.

My question is simply this: Can anyone here recommend a good book or online training course which will give me the knowledge I need to maintain this system and trouble shoot it? I have searched online and there are literally hundreds of such books and it is like wading through a swamp. With such a small network, I am sure I can learn what I need, but if someone can recommend a good training/reference book that you have personal knowledge of, I would appreciate the recommendation.