You could NAT the 10.1.0.0/24 IP addresses before they enter the VPN at the remote end.
If the traffic is only ever intiated from the new site you could hide all the 10.1.0.0/24 addresses behind one IP address which would need to be routable back to the new site.
If traffic needs to be initiated both ways then you'll need to set up one to one translations for the 10.1.0.0/24 addresses. Again the translated addresses used would need to be routable back to the new site.
Here's a link to a Cisco doc on Overlapping Networks
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080093f30.shtml
HTH