There are 3 companions in the game so far:
The Dog: You can find him in the forest where you need to save him by defeating the monster. If you decide to leave the dog you will block him permanently from being your companion, so don't go there unless you're preperd
Robin: You can find him in Dr Coppy clinic in Greyfold Eastside. To have him to join the team you need to pay for his body change treatment (200g). You can either make him more feminine (and "romance" him) or make him more masculine. You can lose Robin if you decide to destroy Greyfold!
Charlotte: You can find her in Nogas. You need to help save Nogas! If you don't you will lose her as a companion (i think). After you met her you have to help her find the ring. Do not r@pe her! Then you just have to upgrade your shack. There are like 3 upgrades. Once its complete you should be able to have a relationship with her and she will join the gang
To crack the computers you need to have 11 inteligence. Can't say what's in them since I truly do not know.