Is this 200 yards through buildings or pretty much line of sight? If it's line of sight, then you should be able to get away with a strong wireless access point at your end, and a strong receiver at hers. It's pushing it, but should be do-able.
If it's not a direct line of sight then it's not really possible (well, it is, but the expense mounts up so quickly it doesn't tend to be worth it.)
Save the whales, feed the hungry, free the mallocs.