String of hearts help!!

Ive had my string of hearts for a little under a year now (got it just before this spring) and ever since it’s always thrived, even in low light. However recently I’ve noticed that it only grows in a small area of my pot and it’s very leggy. It’s growth is incredibly slow right now, but I’ll put that down to it being winter and I’ve now moved it by my window so it gets some sun in the evening. Is there anything I could do to help fill it out more?