Do i need to apply for the green card to be able to obtain the I-551 stamp?

I just found out i lost my green card and i travel to venezuela in 3 weeks! I have no money to pay for one because i am a college student and i dont work. I am traveling with my family? I am calling the USCIS office tomorrow, but i came here to ask the community about it. If you guys can provide me with any advice or information. Thank u .