Just google it, you'll find many answers, I found this guide is really helpful.
Don't know how to retrieve samsung galaxy text messages, just follow the guide.
how to recover deleted samsung contacts
And remember root your phone at first, or the app can't detect your phone successfully. And stop saving new data to your computer, or the deleted data will be covered.
![Image](http://www.sony-ericsson-recovery.com/images/resources/android-message01.jpg)