If it is your router then edit your settings, if it is a router that is controlled by a 3rd party then you need a VPN like
http://bit.ly/vpnpunch but this is a program you need to install and so needs Admin rights to your PC.
You can edit the lan settings of your browser to use a proxy IP address but most of these are not secure, some show your id and so will alert whoever it is you are trying to bypass which may get you fired if it is say a work PC.
When you use a proxy everything you type can be captured, so I would not use one to access anything secure.
If you want to know what they can see about you visit http://www.ipaddresslocation.org/ from that IP you can be identified.
The VPN mentioned is useful for accessing sites as if...