Betty (The Idiot's Lantern)

Betty was Tommy Connolly's aunt who visited Grandma Connolly's house to watch the Coronation on Eddie's new television set. She suggested that Eddie should beat his son, Tommy, to stop him growing up a "mummy's boy". Betty, along with everyone else watching the Coronation, nearly had their faces sucked into the television by the Wire, but were saved by the Tenth Doctor. (TV: The Idiot's Lantern)

Behind the scenes
Dialogue in The Idiot's Lantern doesn't directly state whether Betty is a maternal or paternal aunt of Tommy. At the very least, however, she is not the daughter of Grandma Connolly as is Rita; Betty, when asking Rita where Grandma Connolly is, refers to her as "your old mum", so it is possible that she is related to Tommy through Eddie's side of the family.