start by downloading SP1 from
here
for post sp1 updates check for updates in windows and note down all updates (KB*****)... then search it on Windows download center and then download. check for windows version before downloading
Microsoft Download center
I googled and did got this link but not much reliable as it was random search..
Unofficial windows 7 32 bit post sp1 updates
this might be infected or perfect continue with your own risk only if you don't wish to download every update individually..