Many commercial-grade switches (HP, 3Com, etc) have what are often called mini-GBIC ports on them. These allow you to plug in modules for fiber. You would probably want a 1000TX-SC connector for the fiber. That would connect it to your main network, and then to something like this:
Local Traffic Aggregator with four RJ-45 (switched, VLAN) ports
...on the remote end (or 1 for each end if you don't want to invest in a new switch with fiber.)
In a 100,000 sq. ft. plant that I did the IT infrastructure for, I had our cabling company run 3 pairs of fiber (all fiber connections involve a pair, and I needed one for a network connection, another for a demarc extension, and a third for redundancy) through flex conduit to the far end of the building to overcome ethernet cabling limitations... about 1,000 feet. Both ends (in the equipment racks at both ends) had a fiber terminator box of some sort (forget the exact name) that then connected to the switches.
Hope that helps.
