Funny enough, I have the opposite problem. I hadnt backed up my Beautiful Widgets correctly, but I DID back up the files for the add on with all the HTC looking graphics for the weather.
Those files are listed in the \sdcard\data\beautifulwidgets folder. Inside there, there are Weatherpack, weatherpack-v2 and a weatherpack-v3 folders - each containing the aforementioned graphics. There are also two files - the forecaseaddon-v2.bwa and forecastaddon-v3.bwa - which I assume are the actual files that run for the forecast addon. I replaced these files over the new ones that were downloaded and everything works (for the forecast screen, anyway) as it did before the major BW graphics update.
I might be able to zip these files and send them to you, whereas they are just images and not the actual installation of BW, it should work. Let me know and shoot me a PM with your email if you want to try it out.