dracaena falling over as is top heavy

My daughters dracaena plant was overgrown & rootbound when it moved into my house in September. We had no option but to repot it. Being the autumn, it wasn't a great idea but we had to do something. New roots aren't growing so plant very unstable. Plant is 6' & very wobbly  - I've tied it to a dining room chair (which we will need at Christmas when the family turn up!)
Help!