We connect to the world through a DSL modem which by necessity is located in the centre of our facility. This modem has four LAN ports. There is a Cat5e line running from one of those ports (LAN1) about 10 metres to our work-room where it connects to the WAN port of a router which links the four computers and two printers on our LAN. In the opposite direction from the modem runs another ethernet line (from LAN2) about 8 metres to an individual workstation.
The modem gets its WAN address from the ISP, obviously, and its LAN address is fixed at 192.168.10.1. The LAN address of the individual workstation is 192.168.10.2 and the WAN address of the router in the main room is 192.168.10.3. The LAN address of the router is 192.168.1.1 and the six units connected to it are .2, .3, .4 etc. The sub-net for everything (except the WAN side of the modem) is 255.255.255.0. DHCP is off in both the modem and the router.
All the computers can get out to the internet. The four computers connected to the router can all print to both printers and move files amongst themselves.
What I want is for the individual workstation which is not connected to the router (and can't be, because of the distance involved and layout of the office) to be able to print and share files with the devices in the main room, i.e., for it to be on the same LAN.
How do I configure the router (and/or the modem) to be able to do that? I've been experimenting with various IP combinations but so far all I've managed to do is lock up the modem twice! (Fortunately the 'reset' button sorted that out.) I also tried linking the individual workstation and the router through a pair of PowerLine devices but the speed hit (compared to the wired gigabit ethernet link) made web browsing unacceptably slow for the manager using that computer. :-(
Thanks in advance for any advice.