Took a look at Proxy Switchy, it works pretty well.
Find a Http or Https proxy, since you are not doing anything *suspicious* you can use any proxy, just pick one with a decent uptime and speed, there are lots of sites with public proxys. Although, some of them monitor your *stuff*
You can use one from this list:
http://www.hidemyass.com/proxy-list/
Anyway to set up, just install and then click Options on Switchy! icon, add a new profile, or modify the current one. (the icon is in your browser upper right corner, looks like a globe of earth)
Tick the radio button on manual configuration, and tick *Use the same proxy server for all protocols.
Find a proxy from the list, for security reasons, you could use encryption, so HTTPS with Anonymity level on High, IF YOU ARE ACCESSING OTHER SITES WITH SENSITIVE INFORMATION DO NOT USE LOW SECURITY OR A RANDOM PROXY!
Low security proxy servers can save your passwords and cause all types of havoc.
If you are really paranoid, you can use Tor and encrypt your whole network traffic
Now, next step, add the IP and Port into your Manual Configurtion, (if you want to use different proxy for HTTP, HTTPS, FTP etc, you can find the appropriate proxys and do that as-well)
Now save your settings, and head over to Switch Rules, add a New Rule, call it whaterver, add the URL, you want to access through proxy server,
i tried for testing purposes http://www.whatsmyip.org/, added it to the URL pattern, leave Pattern Type to Wildcard, and select Proxy Profile, whatever you named yours earlier. Save settings again,
Now you are all set, left click on proxy switchy button and choose Auto Switch mode.
Now if the URL you entered in the settings is navigated to, it will switch the connection from direct to specified proxy.
If you want i can make a video and show you how its done, if you still need help or something.