Yeah I was going to mention you usually can use a different router then the one provided by your ISP. Might not be an option for you. Depending on where your located, you may not have a lot of wifi near, or too many WPA's that aren't easy to crack, etc. So one thing to look into is building a long-range home-brew antenna. Get one of these: Alfa AWUS036H 1000mW and look unscrew the antenna on that one and build a custom bad-ass one. I think they have them in 2000w and 5000w now, you could go like over a mile with that potentially.
There's sites an examples all over the net for this. Or you can just buy everything for probably under $60-$100 pre-made. You can make a coffee can antenna for next to nothing and just buy that adapter I mentioned, or one like it. That one has the driver or injecting packets (RTL8187), etc. http://www.google.com/search?q=homebrew+wifi+antenna
That search brings up all the sites I would have mentioned in the top 5, so there you go.
Quidquid latine dictum sit, altum sonatur.
- Whatever is said in Latin sounds profound.
Omnis Vestri Substructio Es Servus Ad Nobis.
- All Your Base Are Belong To Us