It's easy enough to set up a redirect on the old site, so people are sent to a new one.
Whether or not it makes sense to do this depends on how much traffic the previous site was getting. If it wasn't much there's no point in redirecting people - it would just make sense to delete the old site and move on.
If there was substantial traffic it makes no sense to start up under a new domain name - it might be better to just redesign the site.
If you do still want to do a redirect, post back here, and one of us tell you how to do it.