Well you can only have one follower at a time and once you get veronica, getting raul is blasphemous. anyways veronica is at the 188 trading post south of New Vegas. it is along the big big road that goes south along the east of vegas. she only needs some talking to and she will come with you.
Raul is in black mountain and you have to fight your way thru tons of super mutants and radiation but once you get to the top he is in the jail and you need like 50(i think) science to get in one terminal and read all entries. this gives u the pass for the other comp and then u can open the door.
well u can have 2, well from what i have experienced, i have MAX and Boomer, or however the guy name is speeled, MAX is the michanical/human dog, i have them both with me everywhere i go, all three of us be kickin a** in the wasteland, our biggest fight together would have to be either the black mountine, or the deathclaws is the querry, we be ownin lol