The only reference I can find to doing transfers (of any kind, one would need to assume) is this:
"7.1.7 The services and offers you receive through WOZA are not for resale and may not be sold or transferred unless the terms and conditions applicable to that service or offer expressly permit sale or transfer." - http://www.wozaonline.co.za/terms
I think you'd need to get in touch with them directly in order to see if a transfer can be done.
That said, I highly doubt you would be able to easily edit the site from that point, as the site builder is tied to their system. So even if they transferred the resulting site to your own hosting, you wouldn't be able to much with it.
As such, I recommend building a new site with a Content Management System, such as WordPress or ProcessWire.