TV Junkie: Doctor Who Season 3

So I was really confused at the start of this season because at the end of the last episode, the christmas special, I thought that Catherine Tate was going to be the Doctor's new partner, but there was no
mention of her at all. Instead, the Doctor meets a medical student named Martha who ends up becoming his partner, so for the first past of this season, I was waiting for Catherine Tate to show up until I realised she wasn't. However, this season has been my favourite so far. It had some of the most exciting episodes and best moments so far, my favourite being the Shakespeare episode with the Harry Potter references :D  This episode also had a lot more about the characters too, Martha falling in love with Doctor but feeling over shadowed by Rose. At the end of this season, the Doctor discovers that he is not the only time lord left, and he comes face to face with with the Master, who is sort of like his version of Moriarty. Martha's family get more involved throughout the season, resulting in Martha choosing to stay at home, leaving the Doctor on his own again. Leaving the question, who's going to be the Doctors new partner?