Forgive my lack of python experience, but I think it would look something like this:
code:
iesettings = _winreg.OpenKey(
_winreg.HKEY_CURRENT_USER,
"Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"
)
value, type = _winreg.QueryValueEx(iesettings,"ProxyServer")
# do something with the value and data.
_winreg.CloseKey(iesettings)