is not posible to connect without shield? im forced to buy one ????
No you are not forced to buy one, it's just that you will have a lot more work in front of you if you don't.
Connecting the VCC to 3.3v from the Arduino is not solving your problems - you also need to adjust all of your data pins etc from 5v to 3.3v.
The site that you purchased the LCD from also sells the shields - something like this is what you need http://www.ebay.com/itm/1pcs-3-2-TFT-LCD-Shield-Touch-Panel-Arduino-/121303991432?pt=LH_DefaultDomain_0&hash=item1c3e480488#ht_4649wt_934. Not sure if this is exactly what you need - you will need to do your own investigations as I don't know exactly what hardware you are using.
You will note that the shield has a number of IC's on board - if you don't want to buy a shield (and they are not really that expensive) then you will need to replicate those components. You may get away with using resistors although that is not the recommended solution.