DHCP on 2 networks

I have to locations licked via a fiber line. I would like to have my one DHCP server on a 10.1.57.0/24 hand out address to my one network directly attached. I would then like to have my router at location 2 which is compliant send dhcp request to my dhcp server at location one, and have it hand out address on a 192.168.15.0/24 range. So far i have been able to setup the router to send request to my dhcp server on the 10.1.57 network.

My question is how do I tell my dhcp server to hand out IP’s in the 192.168.15 range to the router requesting the DHCP address?

I currently have 2 nics in my server, running W2K3. For the live of me I cant figure out how to bind the 192 range to the other building.