Given that it is only twenty miles you might get a good rate on a p2p T1 between sites. This would probably be the cleanest solution. (In the US?)
If that is too much $ you can do a broadband internet drop at each site and VPN
between sites. I am a Cisco junkie, I would think a pair of PIX 501's would do it for you.
Your addresses cover 772 usable IP addresses, I think you misunderstand (or mistyped) the ip info. Also if those IP subnets were not assigned to you by your ISP (probably not) it means you are not using private addressing outlined by RFC 1918, it may effect your ability to hit real websites in those ranges.