I can't update to 7.0.3

Hey Silverwings13,

First, try connecting to your computer and updating through iTunes. Then, follow these steps if you receive an error or alert message again:

1. Install the latest version of iTunes.
2. Verify that your computer operating system is up to date. If an update requires a restart, check for updates again after restarting.
   • On a Mac: In the Apple () menu, choose Software Update. Install all available updates.
   • On a Windows PC: Go to the Microsoft Windows Update page.
3. Check your security software: Note: Most restore issues are caused by out-of-date or incorrectly configured security software, firewalls, and network router settings or firmware.
   • Isolate the issue to third-party software.
   • Update security software.
   • Properly configure your security software.
   • Temporarily disable or uninstall your security software.
4. Temporarily remove any unnecessary USB devices, leaving only your iPhone, iPad, or iPod touch, the USB cable that came with your device, and a keyboard and mouse, if necessary.
5. Restart your computer and try again.

Note: To perform some of these steps, you need to be logged in to the computer as an administrator. If you are not sure if you have administrator access, contact the owner of the computer or the system administrator.

via: iOS: Troubleshooting update and restore issues

http://support.apple.com/kb/TS1275

If you're receviing a particular error message, try this article:

iTunes: Specific update-and-restore error messages and advanced troubleshooting

http://support.apple.com/kb/TS3694

Welcome to Apple Support Communities!

Have a good one,

Delgadoh