Without an exchange account, this is the only way to do what you want:
Download the iPhone Configuration Utility
http://support.apple.com/kb/DL851
This is for windows:
http://www.apple.com/downloads/macosx/apple/application_updates/iphoneconfigurat ionutility21forwindows.html
And then:
1. Click on the Passcode tab, and check Require Passcode on Device. Check the various options/restrictions you want to enable.
2. When you are all done, click the Share button at the top of the window. An email will open with a configuration profile attached. Send the email to your iPhone.
3. Open Mail on your iPhone, and open the message with the configuration profile attached. Click on the profile attachment, and then follow the on-screen prompts to install the profile and set your new long passcode.