Welcome to the wonderful world of photography Paz!

Phool gave you some great advice!
I will add that great glass is not cheap. The lenses are the camera's eyes, so you don't want to scrimp on them.
The T3i is a great camera that is capable of taking some totally awesome photographs, so you are off to a darned good start!

Congrats!

Your next step should be to LEARN the camera's controls and settings. Then you can get out of the little green (auto) box on the settings wheel and delve into TV, AV and M settings. There is where you will get your best photos.

When you get the controls mastered it's time to start spending some serious money on lenses.

It's an Expensive Disease!

Feel free to ask questions, we are always willing to help out a newbie!

If you want, PM me your questions. I'll answer all I can and if necessary PM you my phone number so I can explain the answers directly!

Dick