If my Cisco 831 is only capable of 10BASE-T for a WAN connection to a corporate VPN server and there re 12 people on this VPN through a 8MBPS cable modem, can this be the bottleneck and reason why our connection is so slow?

I have a 8mbps cable modem connection for our small business office and a Cisco 800 Series (model 831) connected to our switch and Comcast (Netgear) cable modem. The modem light is amber to the port where the 831 is connected. I have been told that t...