Repeater - bridge - weak signal - hardware?

Hi all,

I have access to a community wireless network, but am at it's outer ranges,
hence connection drops and when it the weather gets rough I completely lose
connectivity.

I'm wondering what my options are in terms of improving connectivity. Guess
i'm thinking there may be a bits of kit that can multitask as
AP/Router/Bridge/Repeater that I can attach an external antenna to and
improve connectivity.

Anyone know of such a beast?