Increase wifi signal strength

[jasonalwaysready]

a colleague has a neighbor who would like to use his kindle on her network. the neighbor lives across the street, let's say 100-150 feet away, no obstructions. the signal strength just isn't quite enough, though he can connect to an unsecured router that is further away from a different neighbor.

any solutions?

diy cantenna?
increase tx signal strength on colleagues wireless router?
would a wireless router standalone (doesn't own his own computer) in the neighbors house on repeater work?

Thanks,
jason