Questions about my freind's bar mitzvah?

So on the invitation it says first they invite me as their son (my friend) is called to the torah as a barmitzah happens in the morning.. Is this the ceremony? What should I wear to it, I'm a girl? Then there's another card that says the celebration continues on saturday at the ice nightclub (I'm assuming this is the "party").. Should I give him the gift at the ceremony or the party? What kind of gift as well? Also, if the mail had only my name on it, does that mean by parents aren't supposed to go?