You probably won't be able to access it and still keep your work VPN useful. When you connect to a VPN generally the VPN will direct all outbound traffic through it, and usually set a proxy for your browser. Since you mention a webpage I will assume it is the second.
To test this quickly, use Firefox or Opera and see if it can get to it. IE, Chrome, and Safari all use the built-in Windows proxy settings (so they will all react the same). If Firefox or Opera can get to it, that was the problem. If this was the case, you can turn off the proxy but this will probably break your connection to the internet when connected via your work VPN.
To turn off your proxy:
- In Internet Explorer click on Tools -> Internet Options.
- Click the Connections tab.
- Click the LAN Settings button.
- Uncheck any boxes that are currently checked.
- Hit OK all the way out.
If that doesn't fix it, your work probably has a device somewhere on their network (or a router that advertises a route to) that has 192.168.1.1. If this is the case, chances are trying to turn off the default gateway would prevent you from accessing the work network while you were connected (since that is the point of the VPN).
Chances are if Firefox/Opera doesn't work, you'll need to disconnect from the VPN to modify your router.