I'd like some advice on setting up our new satellite internet system.

I need to connect 3 computers to a satellite internet modem.

Computers 1 and 2 are in a building with steel siding, within 25' of
one another and in two separate rooms.
Computer 3 is in a separate wood-sided building 350' away in direct
line of sight.

Here's my current plan:

Place a draft-N (or would g be better?) wireless router (connected to
satellite modem) next to computer 1 and connect by cat6 cable to
computers 1 and 2.

Roof mount directional antenna above computer 1 (12' distance to roof)
and aim it at the building 350' away where computer 3 is located.

Questions:
Which router do you suggest that will connect to an external roof
antenna on the roof?

Which directional antenna do you suggest?

What other product recommendations or setup ideas do you have to make
this network work?

Thanks.