What tool are you using to replicate the VM? It'll likely be OK and depending on the tool you may just need to restart it with a fresh copy.
With your datastore you'll first need to add the disk and expand the array at the RAID controller level. Once that is done you should boot up your host and verify that things are still Ok. After that go to Configuration > Storage, bring up the properties for the datastore and you'll see an option to Expand it. Then follow the wizard to do that.
Is this a fresh ESXi 5 install or an upgrade from a prior version?