Hi - I've also got a couple of posts on how to do this on my blogs.
If you are on a remote server /host - does that mean you have remote access to the server? Or does it mean you have shared hosting.
Remote Access is by far the quickest and most reliable way in my opinion and here are some details on how I have upgraded some of my sites -
One was 4.5 > 5
http://blogs.xd.com.au/2009/12/28/UpgradingASiteToDNN5.aspx
The other was a bit older -and has some more images -
http://blogs.xd.com.au/2008/06/06/Ugr...
The key is to get a backup prior to starting.
You can use the artisteer product on other versions but it is fiddly and there are some benefits in moving forward to later versions of dnn.
If you have no experience what soever in upgrading, then it could take you a while. It's doable and possible, but knowing what you need to do is of course better.
Sometimes I have suggested to some people to export their site content and put onto a new build of dnn as for some, I think it's also an easier approach.
Hope this gets you on your way too.
Nina