I own https://wonderproxy.com/ and the primary thing we sell our customers is "a server where we say it is so you can test your localization", and we have problems _all the time_. So I've been where you are, with the added bonus of having customers yelling at me because Google thinks my Madrid server is in France.
There's no real good options here, different people use different databases of different ages with different procedures to update (if they have one at all). MaxMind (http://maxmind.com) is pretty good at updates, as are most of the free options (like ip2location http://www.ip2location.com/). Google (which powers a lot of ads, and their own country redirect) has a form (https://support.google.com/websearch/contact/ip) which seems to pipe directly into
Most GeoIP providers want to handle things in large blocks, not one IP at a time. If you can convince your ISP (generally by pointing them at a few forms) to send in corrections they'll be able to correct their entire IP space all at once, which may be handled faster, or at least cover you now and next time your IP changes. Once these are submitted expect a delay of 2weeks -> before anything starts to get better.
Beyond trying to correct people, buying a cheap server from Linode and VPNing through should be a decent work around. If you set up an OpenVPN server, several routers are capable of connecting and routing all their data through them automatically, so you wont need to configure each device individually. Linode is a decent option as their servers are fast, stable, and you'll effectively only pay for half your symmetric bandwidth as inbound is free.