|You could do this with single mode fibre optic cable, it has a segment length of something like 25 km's.|
However, it will be very expensive.
I would suggest you call your local telephone company and ask if they can accomodate you and how much it would cost for the hookup and also the monthly price.
Your best bet may be to get a highspeed internet connection (either cable or DSL) in both locations and then buy two SOHO Router's capable of creating a VPN. Then, establish an encrypted VPN tunnel between the two locations.
The VPN idea is bound to be a whole lot cheaper.