as far as I know:
normally, even if you do not have a support contract, the software can be used on new hardware. It has to be validated though, and you need support for this (this is not the "normal" functional support, it's just to validate the software on a new server.
If the version you have doesn't run on current versions of operating system/database, you will need to update to a later version. For this, you will need a support contract. It might be less expensive to buy the software again than to renew the support contract.
Are you running on Windows or Unix? You might try virtualizing the existing environment, although I'm not sure this will work.