Some thoughts:
1) Is your machine a laptop? If so, and if you have a friend with a larger monitor, plug your laptop into that so you can make the window smaller.
2) Does your machine have a brand-name graphics card? Some come with add-on desktop extenders that support panning desktops (desktops that are larger than the physical screen).
3) If you have an external monitor, you might be able to set the resolution of the graphics card to larger than the monitor can display. You won't be able to see everything, but you should be able to see a corner of the dialog box so you could resize it.
4) If you can see any edge of the dialog and get a resizing arrow, even the left or right edges, then the "sizer" utility might help. See
http://www.brianapps.net/sizer/. Disclaimer: I have never used this utility.