Strictly speaking, she has no full siblings but only a half-brother, Tony Tyler. Tony is the son of Jackie (Rose's mother) & the alternate Pete Tyler of the "Pete's World" universe. Rose's father was the Pete Tyler of the main universe & he was killed in a road accident while Rose was still an infant (as seen in "Father's Day"). Tony was mentioned in "Journey's End", although we'd earlier been told (at the end of "Doomsday") that Jackie was pregnant.
Since Tony's father is a parallel version of Rose's own father, Tony is very much closer to being a full brother than a half-brother with an entirely different father would be.