Most likely you're using the vpn connection's default gateway to browse (this is the default behavior when you create a VPN connection). Here's how to change it:
1) Open network connections
2) Right click your VPN connection and do properties
3) Select networking tab
4) Double click on TCP/IP
5) Click on Advanced
6) Uncheck "use default gateway on remote network"
7) Click Ok, Click Ok, etc...
That whould work for you.
Nate