No problem! I'll need to find out if USB Debugging is on before we choose how we get another ROM on there to sort you out.
There's a section in this post called Mini SDK: http://androidforums.com/faqs/443072-adb-guide-updated-12-05-2011-a.html
Download the zip file from that, then follow the instructions for the install. Once setup, connect the phone to the PC open a command prompt, navigate to the SDK-tools folder you created and type adb devices. That will help me ascertain if USB Debugging is enabled and what we need to do next. If you see your phones serial number, we should be good to go.
Does that all make sense?
There's a post here with pics on the adb device stuff if it helps too: Forcing Apps to install to the SD Card without root
I need to head out for a bit so if you want to hang fire with trying the above till later, and I can go in to a little more detail if you want? If it all looks ok, then fire on, post the results and I can see what we need to do when I'm back.