I know there are a lot of you AOers out there that know a lot about this subject, and I haven't messed with wireless too much, so I just thought I'd ask:

I have a LAN (wired), that has about 30 PCs on it. I have two wireless enabled laptops that I plug into the network, use for training, presentations, et cetera. My company is having an off-site sale about 500-700 feet down the street. In the past we would've had an outside vendor come and setup an antenna, hook us up to his wireless service, and use remote access to login to a PC on the network. This costs us $200 for 2-3 days of wireless service! I thought there has to be a better way. I believe we have line-of-site to where we will be, so... I figured I could get a couple directional antennas and get the laptop(s) on the network. It would save us time and money. We do these sales 2-3 times a year so it would really save us money in the long run.

The main issue... SECURITY. We have extremely sensitive information on our network, and cannot afford any compromise of it. Here's the thing... I'm sure I could hook it up OK, but I don't know enough about wireless to ENSURE security (well I guess you can never ensure security, but you know what I mean).

Do you have any suggestions on how to set this up? Hardware to use?

I know this is really broad, but I would really appreciate any help on this.