What is my highest note in my voice?

[High]

My choir teacher had me do a voice lesson with her so she could figure out what my range is. I am a baritone with a very broad range all the way from deep bass to a decent high tenor.

So she played the keys on the piano going one night higher and higher..Do re mi fa so la ti do or la la la la la la and I got high I believe ..she said my highest note was a 'G' ..now I really don't know what that is cause when I look the notes up on the internet i see stuff like B4 A4 F4 Middle C A2 and crap but idk what note I sang can someone tell me what the note was that i probably sung and link me to the note?

[Sonic Boom]

Well middle C is the middle note on a piano keyboard. So G is another 4 white keys to the right. The next highest G is one octave up (8 keys apart).

[Mortal Coil]

Middle C is C4, so if your highest note is G4 then it's the G above middle C. If it's G5 (which I really doubt it is, but I don't know you) it'll be one octave higher.
Now, on to which one is G:
on a piano, the black keys are in 2 groups: one of 2 black keys, then another of 3 black keys. The G is the white key directly to the right of the first black key in the group of 3. In other words,
http://i2.ytimg.com/vi/y4xojfkXioI/hqdefault.jpg

[Hermes]

As we weren't there we can only take an educated guess.

The note G4 is one possibility and maybe the most likely. This is the first G above middle C (middle C is C4).

For a typical choral tenor this would usually be a pretty high note but that is because the people singing the tenor part in choirs are often actually lyric baritones and also don't have the benefit of as much training as an operatic tenor. For an operatic tenor this would be a fairly common note - in the upper part of the voice but still with a few more notes to go. Lots of pop and rock music includes this note.

Another possibility is G5. For a baritone the chances of singing that note full voice are just about zero and even in falsetto many baritones would not be able to sing it. This note is up in the soprano range and is already higher than most female pop singers regularly sing.

To get a better idea you could listen to this recording (http://www.youtube.com/watch?v=3-rre_BXxC0) of Gethsemane from Jesus Christ Superstar. The note sung on the word "die" at 4:02 is the higher of the two Gs, G5. The lower G, G4 appears at 5:27 on the word "Nail" and is the final held note.

You may also find it useful to understand the notation with a letter name and a number. The letter names repeat in each octave to to define exactly which 'G' we need an octave number. As another poster commented C4 is middle C - roughly centre on a piano keyboard and equates to the leger line below a stave in the treble clef and the leger line above a stave in the bass clef. The number change on C so the D immediately above middle C is D4 and so on upwards to tenor top C which is C5. The B immediately below middle C is B3 and likewise the notes going downwards until you get to the C one octave below middle C which is C3 and the B below that is B2.

As a baritone, apart from the two Gs mentioned above as possible top notes you would expect to be able to sing G3 and maybe also G2.