I need to create a bridge between 2 locations. Building A has Internet. Building B has no internet. Distance is about 250 Ft. I need secure connection preferably WPA. I would also like the unit to function as an access point at the same time. I need to be able to connect an external antenna so the unit will be inside and the antenna outside. I don't want to spend more than $150 on each bridge. Please do not give me a link to a network site's general page. I would like specific devices.