If my iphone 4s is defective can I get an iPhone 5?

I've had this iPhone 4S since iOS 6.0.1 and it started off occasionally crashing randomly.
( just shutting off and back on ) and now I'm on iOS 6.1.3 and randomly on whatever app I'm on it will just exit out of the app and bring me back to the home screen. I want to know if I can get an iPhone 5. I'm not due for an upgrade until April 20th 2014 and I don't want to pay the $250 extra just to upgrade.

If you have a warranty just contact them and if you don't your out luck your gonna have to restore your iPhone back to its regular settings this means All Data goes Bye Bye unless you have icloud

You will not be able to get an IPhone 5 without either paying for the phone outright or and early upgrade few since you are not due for an upgrade currently.

Since the phone seems to be having issues, you need to perform a restore from iTunes on your computer. Make a backup before you do this. All of your information is automatically saved to iCloud as long as you are logged in via your Apple ID (you can check this in Settings > iCloud). Everything will be restored from backup, and iCloud will restore your apps, backgrounds, contacts, etc.

If you're still having problems with the phone after the restore, you can take the phone into an Apple store (apple.com/retail) for more help. Note, however, that any services may incur a fee if you are out of warranty. If you're in warranty, while you're unable to upgrade to the 5, they may be able to get you a new 4S.

Please be sure to do a restore before you take the unit into the Genius Bar. They will send you home if you're experiencing software issues and have not done so before your appointment with them.