Over my limit - very strange behaviour

[#1]

I just checked my email and found 2 emails from F9 saying I had gone over my quota on my f9 webspace by 82,004 KB which is odd, its on my original F9 webspace but I have no idea why it went over, my webstats look a little like the image attatched.  Now I have no idea what-so-ever what happend at 1PM for my website to suddenly get popular.
My biggest referrer is apparently:
1 1359 86.40% http://www.sg.hu/listazas.php3
I have no idea what that site it, nor any idea about how they found that many files on my web site, I don't have that many.  Has this happened to anyone else? Does anyone speak Hungarian so knows what the heck that site is about that has caused me this hassle?  I had directory browsing off, so it was a direct link to a file, but I don't know *what* file it was as the Webstats are not currently showing it.
/edit - found it, someone linked to my funny forum signature so billions of hungarians had a peek which took me over, I've stuck it on the new PN webpsace so going to have to disable hot linking through .htaccess now

[#2]

I have had the same problem today. My average daily use has been around 70-80Mbytes with maximum bandwidth usage of about 130Mbytes. I have not had a chance to examine my stats properly yet so am not sure what caused this spike.

[#3]

Images in forum signatures:
Find a very old post of your own that no-one is likely to look at. Edit the post and attach the images you want in your signature to that post which will upload them to the Plusnet server.
Now find the URL for the images on the Plusnet server and use that in your signature.
Edit: You can use the thumbnail or the full image so you could make one link to the other. Example:

[#4]

I used umm, rewrite or something in the .htaccess file, so now it *should* just give a big red cross in places where I don't want it to be linked to, but will show in places where I do want it linked to. 
Now that I have that sorted, I should see about getting my site unarchived