If your only going to be spending $40AUD a rim then it would be too expensive to get a wheelset. I'm not sure about spokes, some say you should replace them others say you can't. Dont worry about the hub, just give it a service (clean out grease/re-grease) and that will make a big differnce. The hubs look like basic stock OEM shimano ones or something, nothing spectacular and unless you're having problems with them dont bother replacing them.