Joanie Steffend was a host on the HGTV show "While You Were Out" from 2004 to 2009. She does not have a sister who was also a host on an HGTV show.
There is no known information about a sister of Joanie Steffend who was also a host on HGTV.
It's possible you're thinking of another HGTV personality or mistaking Joanie Steffend for someone else.