Does anyone have suggestions on the best solution for connecting two buildings about a mile apart via 5 GHz Wi-Fi?

We have two antennas tuned to the 5 GHz range with a 28 dB gain and N-type male connectors at the end of their coax cables. The goal is to be cheap (<$400 if possible) and to be reliable even in Michigan snow storms.

The antennas will be line-of-sight or almost line-of-sight, with trees being the only major obstacle between the two points. (Our two buildings are the two tallest in the span the signal would travel, and there are a number of homes between here and there so keeping up in the 5 GHz range, out of 802.11b/g's space would be nice.)

We are looking at getting 802.11a equipment right now and powering them up to beam to the appropriate location, but that is looking like costing a fair chunk of change. (Airaya is what was pointed out to use previously, but that would cost $1,200, a fair bit more than our goal of $400.)

This would be used to replace a T1 line we are paying $250 for a month and only gets us a 1.5 Mbps connection that is being regularly maxed out, so even maintaining a strong 10 Mbps connection will make us happy.

Any feedback and comments are greatly appreciated. :-D