Best Network Configuration for Security...

I am running Windows 7 x64 Ultimate on my desktop (home) and Windows 7 x64 Pro on my laptops. I bring my personal laptop to work which I use for emails and browsing. There is sensitive information that I would not like to share for obvious reasons. I am running into a problem making sure the information is not in "shared" mode while at work. Work has their own network, which I am unable to connect to because the Sys Admin is lazy and will won't provide me a VPN connection directly to the system. So what I have done is use the public WiFi that we make available to our customers and connect through my own VPN off the public WiFi system. I want to make sure that I am not inadvertently sharing documents or other information doing so. When I connect to the network at work I use the "Public" setting. What settings do you recommend?

What makes it more difficult is I have a similar situation at home, in which we have one internet connection through a router coming in and several people use the system. The location of the router is actually upstairs where I do not have access to, I use a Netgear WNR2000 v2 (I rent out rooms in my house), so I am forced to connect to the router wireless. I personally am not a gamer, but one of the tenants is. I almost always use my VPN service at home to connect, but I am unsure if this is the correct set-up. I don't want to share my printers, video, etc. with everyone in the house. I am using Norton 360 for protection with Firewalls and Anti-virus software. I connect through Golden Frog VPN service for security. I am going to connect my desktop Gigabit switch with my devices but again want my system secure, but not limited because of my situation. It is safe using the router for access and then creating this "sub-network" for my devices (for the router I am the admin)? Is there a better method or suggestion that one might have. I would really appreciate the input for this complicated matter. Should I change my workgroup for home and work? Currently its the default WORKGROUP domain for both.

Thanks again...