I think you should get a boy! I love having a boy and a girl and I love them both dearly, but I truly feel that there is no better pet than a male yorkie who is fixed early (around 4-5 months). My little boy is SO loving and sweet.
That would be so awesome if you could get a little boy from the same parents. Both of my yorkies have the same parents, too. Hootie is from a subsequent litter.