From http://www.smallnetbuilder.com/lanwan/lanwan-reviews/31746-cisco-rv180-vpn-router-reviewed?showall=&start=3, you can have a good feel of the network performance of RV180.
Definitely, there is something wrong if you're only getting 10Mbps or so.
Try disabling all firewall, QoS, and when you measure performance, try for a remote site as near as possible. If you're in USA, you won't want to use a speed test server in China, for example.